Image copyright AFP Image caption Newspapers described serpentine queues at ATMs 
 
 Indian Finance Minister Arun Jaitley says "honest people" have no need to worry about a decision to scrap 1,000 and 500 rupee notes. 
 
 Mr Jaitley said the move would flush out tax evaders, adding that all old notes deposited in banks would be subjected to tax laws. 
 
 The surprise move, announced on Tuesday evening, is part of a crackdown on corruption and illegal cash holdings. 
 
 The announcement was met with shock in India. 
 
 Media described the move variously as a "surgical strike" on tax evaders in the country's overwhelmingly cash-based economy and a "big bang note". The banknotes declared illegal tender represent 85% of cash in circulation in India. 
 
 Mr Jaitley said that the move would also help India move towards a cashless economy, saying that farmers could "now keep their money in banks". 
 
 He added that new 2,000 (about $30; £15) and 500 rupee denomination notes to replace those removed from circulation would be injected into the economy over the next "three to four weeks". 
 
 On Tuesday there were long queues at ATMs as people tried to withdraw 100 rupee notes, which are still legal. 
 
 Banks and ATM machines were shut on Wednesday. 
 
 The most affected are likely to be small traders, vendors and labourers but newspapers were quick to point out that India's wedding season, due to start in a few days, will also be hit hard. 
 
 Media playback is unsupported on your device Media caption One woman says the unexpected change will make it tricky for her to pay to get to work 
 
 "Black money and corruption are the biggest obstacles in eradicating poverty," Prime Minister Narendra Modi said in his address to the nation on Tuesday evening. 
 
 He said the move would "cause some hardship" but asked people to "ignore" it, calling the step a "celebration of honesty". 
 
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 People will be able to exchange their old notes for new ones at banks over the next 50 days but they stopped being legal tender at midnight on Tuesday. There are also going to be limits on cash withdrawals from ATMs starting on Thursday. 
 
 The move is designed to lock out money that is unaccounted for - known as "black money" - which may have been acquired corruptly, or be being withheld from the tax authorities. 
 
 Finance Secretary Shaktikant Das warned people with large amounts of hidden cash that banks would closely monitor the exchange of old notes for new ones. 
 
 How long have people got to change their old notes? 
 
 The 500 and 1,000 rupee notes are the highest denomination notes in the country and are extremely common in India. Airports, railway stations and hospitals will only accept them until 11 November. People will be able to exchange their money at banks between 10 November and 30 December. 
 
 How much 'black money' is there in circulation? 
 
 The actual figure is unclear but correspondents say the issue of "black money" is a huge problem in India. The idea here is to lock out money that is unaccounted for and make it visible for tax purposes - banks will be happy to exchange a few thousand rupees, but will be asking questions of those who turn up with hundreds of thousands or millions in currency. 
 
 Is there a limit on the amount an individual or household can cash in? 
 
 It seems not. An individual can put as much as he or she likes into the bank - but withdrawals are limited so the banking system may end up being flooded with cash. 
 
 Image copyright Indian government Image caption The government has issued flyers explaining the changes 
 
 Government guidelines say it is possible to exchange 4,000 rupees - but it is not clear if this is per day or in total. If there is a legitimate explanation for the cash, the authorities say, it will be possible to exchange it. 
 
 Do you have 500 and 1,000 rupee bank notes that will need to be changed? Get in touch and email haveyoursay@bbc.co.uk. 
 
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 Read our terms and conditions. ||||| India has discontinued its two largest rupee notes in a shocking move against corruption. 
 
 Notes worth 500 and 1,000 rupees will be invalid starting at midnight local time, Prime Minister Narendra Modi announced during a televised address to the nation. 
 
 The unexpected move is designed to fight against corruption and money laundering, Modi said, calling them "diseases" and "obstacles" to the country's economic success. 
 
 Modi said that policy changes had largely failed to root out corruption. Two years ago, he said, India was ranked 100th in terms of global corruption perception, and the country has only improved to 76th. 
 
 Related: India's tax dodgers still hiding hundreds of billions 
 
 The idea is that Indians who have stockpiled undeclared income will now be forced to come out of the shadows. 
 
 "This step will strengthen the hands of the common man in the fight against corruption, black money and fake currency," said Modi, who leads the ruling Bharatiya Janata Party. 
 
 Brilliant Move by @PMOIndia on Demonetisation of current Rs.500 and Rs.1000 notes. Biggest Crackdown on BlackMoney in any Nation's History — ashutosh mishra (@ashutos76653335) November 8, 2016 
 
 But the ban could also spark a mad scramble as ordinary Indians seek to exchange or deposit their cash. Modi said citizens have 50 days to deposit at banks and post offices. Hospitals will be allowed to accept the banned notes for another three days, until Nov. 11. 
 
 That transition will not be an easy task. The Reserve Bank of India (RBI) estimates that there are 16.5 billion 500 rupee notes and 6.7 billion 1000 rupee notes currently in circulation. ATMs will be shut on Nov. 9 and 10 to help implement the change. 
 
 Related: India's new central banker serves up surprise interest rate cut 
 
 The central bank is also preparing to issue a new series of 500 and 2,000 rupee notes, which are slated to enter circulation by Nov. 10. 
 
 Until then, the largest legal bill in circulation will be the 100 rupee note, which is worth only $1.50. 
 
 RBI issues ₹2000 note in new series pic.twitter.com/7Ob2j1t6Ab — ReserveBankOfIndia (@RBI) November 8, 2016 
 
 In a country where taxi drivers and shopkeepers are already reluctant to part with small bills, the sudden policy change could complicate business transactions in the short term. 
 
 Indian social media users widely praised the decision, calling it a "bold move." There were also, inevitably, plenty of jokes. 
 
 Two Minutes Of Silence For People Who Are Standing In Queue At ATMs Right Now, Having No Clue About The Ban On Rs 500 And Rs 1000 Notes. ;) — Sir Ravindra Jadeja (@SirJadeja) November 8, 2016 
 
 Don't worry folks.. winter is coming.. people with rs 500 and rs 1000 notes black money can burn it and stay warm.#IndiaAgainstCorruption — Shrinidhi (@_shrinidhi_) November 8, 2016 
 
 India is believed to have lost out on over $100 billion in uncollected tax, a large percentage of which is illegally stashed offshore. 
 
 Only 2% of Indians pay any income tax at all because most people work in the economy's informal sector that includes jobs such as construction laborers and road side food sellers. 
 
 Modi also touted the move as an anti-terrorism measure, saying that "enemies across the border have run their operations using fake currency notes," a reference to neighboring Pakistan. 
 
 "The 500 and 1,000 rupee notes hoarded by anti-national and anti-social elements will become just worthless pieces of paper," he said. ||||| Image copyright PRAKASH SINGH/AFP/Getty Images 
 
 India is in the middle of an extraordinary economic experiment. 
 
 On 8 November, Prime Minister Narendra Modi gave only four hours' notice that virtually all the cash in the world's seventh-largest economy would be effectively worthless. 
 
 The Indian government likes to use the technical term "demonetisation" to describe the move, which makes it sound rather dull. It isn't. This is the economic equivalent of "shock and awe". 
 
 Do not believe reports that this is primarily about bribery or terror financing, the real target is tax evasion and the policy is very daring indeed. 
 
 You can see the effects outside every bank in the country. I am in Tamil Nadu in the south of India and here, as in every other state in the country, queues of people clutching wads of currency stretch halfway down the street. 
 
 Image copyright NARINDER NANU/AFP/Getty Images Image caption Long queues of people wanting to exchange the old notes have formed across India 
 
 Mr Modi's "shock and awe" declaration meant that 1,000 and 500 rupee notes would no longer be valid. 
 
 These may be the largest denomination Indian notes but they are not high value by international standards - 1,000 rupees is only £12. But together the two notes represent 86% of the currency in circulation. 
 
 Think of that, at a stroke 86% of the cash in India now cannot be used. 
 
 What is more, India is overwhelmingly a cash economy, with 90% of all transactions taking place that way. 
 
 And that is the target of Mr Modi's dramatic move. Because so much business is done in cash, very few people pay tax on the money they earn. 
 
 According to figures published by the government earlier this year, in 2013 only 1% of the population paid any income tax at all. 
 
 As a result huge numbers of Indians have stashes of tax-free cash hidden away - known here as "black money". 
 
 Even the very poorest Indians have some cash savings - maybe just a few thousand rupees stored away for a daughter's wedding, the kids' school fees or - heaven forbid - an illness in the family. 
 
 Image copyright Dennis Brack-Pool/Getty Images Image caption India's Prime Minister Narendra Modi gave only four hours' notice of the move 
 
 But lots of Indians have much more than that. 
 
 It is not unusual for half the value of a property transaction to be paid in cash, with buyers turning up with suitcases full of 1,000 rupee notes. 
 
 The size of this shadow economy is reckoned to be as much as 20% of India's entire GDP. 
 
 Mr Modi's demonetisation is designed to drive black money out of the shadows. 
 
 At the moment you can exchange up to 4,500 (£48) of the old rupees in cash for new 500 (£6) and 2,000 (£24) rupee notes. 
 
 There is no limit to the amount that can be deposited in bank accounts until the end of December, but the government has warned that the tax authorities will be investigating any deposits above 250,000 rupees (£2,962). 
 
 Breach that limit and you will be asked to prove that you have paid tax. If you cannot, you will be charged the full amount owed, plus a fine of 200% of the tax owed. For many people that could amount to be pretty much the full value of their hidden cash. 
 
 This is brave politics. Some of the hardest hit will be the small business people and traders who are Mr Modi's core constituency. They voted for him because they believed he was the best bet to grow the economy and improve their lot. They will not be happy if he destroys their savings. 
 
 Image copyright PUNIT PARANJPE/AFP/Getty Images Image caption Businesses will no longer take 500 and 1,000 rupee notes 
 
 Mr Modi says he is simply delivering on his pre-election promise to tackle corruption and tax evasion. 
 
 He says he warned that he would squeeze black money out of the system and had already offered amnesties to those who declared their black money holdings. 
 
 And, so far at least, the policy seems to be popular, in spite of the long queues and the fact that much day-to-day business in India has ground to a juddering halt. 
 
 Most Indians resent the fact that many of the richest among them have used black money to evade paying their fair share of tax and are happy to suffer a few weeks of what Mr Modi called "temporary hardships" to see them face justice. 
 
 They also recognise the benefits of drawing more people into the income tax net. 
 
 India has very low rates of tax compared to many other countries. The tax-to-GDP ratio - how much tax is raised as a proportion of the output of the economy - was 17% in 2013. 
 
 The average across the economies of the Organisation for Economic Co-operation and Development - a club of mostly rich nations - was over 34%. 
 
 Demonetisation is part of a wider project to draw Indians into the formal economy and to get them to start paying the tax they owe. 
 
 Image copyright SAM PANTHAKY/AFP/Getty Images Image caption There is no limit to the amount of old notes that people can deposit in bank accounts until the end of December 
 
 Curbing tax evasion is part of the agenda for the "aadhaar" scheme, a giant digital database designed to give hundreds of millions of Indians a unique ID, and of the new Goods and Services tax. 
 
 And reducing tax evasion can only be good for India. The more money it raises in tax, the more it has to spend on useful stuff like roads, hospitals and schools. 
 
 The more the country spends on public goods like that, the faster the Indian economy is likely to grow - or so the argument goes. 
 
 So the big question is: will it work? 
 
 Some economists have questioned the decision to introduce the 2,000 rupee note. They say if the policy is designed to force people into the banking system why issue a higher denomination note - presumably an even more convenient vehicle for black money transactions? 
 
 But the headlines about chaos and confusion are a bit misleading. 
 
 There have been virtually no reports of violence despite the huge disruption this policy has caused. 
 
 Image copyright PUNIT PARANJPE/AFP/Getty Images Image caption The new 500 and 2,000 rupee notes are in short supply and banks regularly run out of them 
 
 The queues are orderly and the worst you hear are the irritated mutterings of those whose days have been wasted standing in line. 
 
 But Mr Modi needs to be careful. The new notes are in short supply and there are not enough smaller denomination notes to go around, so the banks regularly run out of cash. 
 
 That cannot go on for long without irritation turning to anger. 
 
 But some queuing may be excusable, because in one regard the policy has already been a complete success: it came as a surprise to the entire country. 
 
 Think what that means. The government managed to plan this audacious policy, printing billions of new notes without anyone letting slip what was happening. 
 
 Reportedly, even senior members of the cabinet were not told what was being planned, for fear that if word got out the entire policy would be undermined. The hoarders would have time to empty their mattresses and launder their stashes into gold or other assets. 
 
 Keeping a secret of this magnitude in India, a country that thrives on rumour and gossip, is nothing short of a triumph and surely a reasonable justification for a few hiccups along the way.
– A surprise announcement out of India Tuesday night is being called by local media a "surgical strike" against currency corruption that's infiltrated the nation, the BBC reports. Per CNNMoney, India Prime Minister Narendra Modi announced that the country's two largest current bank notes—the 500-rupee note and 1,000-rupee note (equivalent to about $7.50 and $15, respectively), which equal about 85% of the cash currently moving around India—were taken out of circulation in their current incarnation as of midnight Tuesday, which the government hopes will lure people out of hiding who've been stockpiling money without paying taxes on it. The idea is to force them to swap the cash for legit replacement money at banks and post offices before the 50-day deadline for such trades arrives on Dec. 30. Experts say there's a preponderance of this so-called "black money" in India, and by drawing it all out in droves, banks will be able to send up a red flag if people come in with large amounts, possibly helping the government catch tax evaders. There are about 16.5 billion of the 500-rupee bills and 6.7 billion of the higher denomination now in circulation (ATMs will be shuttered Wednesday and Thursday so more notes won't be introduced into the flow). In place of the now-almost-worthless notes, the government will issue new 500- and 2,000-rupee notes with images of Gandhi on them, the Wall Street Journal reports.