QI: Some Quite interesting facts about Bhutan Less than 16 per cent of Bhutan is arable but 94 per cent of the population are dependent on agriculture, the highest proportion in the world. Bhutan has the world's highest unclimbed peak, Gangkhar Puensum. The mountain is sacred and the Bhutanese government has banned mountaineering on any peak above 6,000 metres (19,685 feet). Happy Bhutan is the world's only carbon sink - it absorbs more CO2 than it gives out - and the only country whose largest export is renewable energy: they sell hydroelectric power. In keeping with the Buddhist idea that humans and nature form a symbiotic relationship, 72 per cent of the country is forested, and it is in their constitution that 60 per cent always will be. This environmental pledge is part of the idea of "Gross National Happiness," whereby the treasury measures progress against "four pillars" - sustainable development, environmental protection, cultural preservation and good governance - rather than just GDP. National sport Bhutan has two national sports, archery and darts. Both are played between two teams that goad each other from either end of long playing fields. Bhutanese darts (Khuru) are heavy and potentially lethal; they are thrown over 20 metres towards a target that is much smaller than a regulation dartboard. National animal The national animal of Bhutan is the takin, an animal so unusual it is in a class all of its own, Budorcas taxicolor. Bhutanese believe their most popular saint, known as the divine madman (1455-1529), created it. When he visited Bhutan he was asked to perform a miracle so he demanded a whole cow and goat for lunch, which he devoured, leaving only the bones. After a large burp he took the goat's head and put it on the cows bones, clicked his fingers and the beast took form and began to graze on the mountainside. Bumthang The spiritual heartland of Bhutan is called Bumthang (pronounced boom-tahng). Residents of Bumthang speak Bumthangka, one of 24 languages spoken in a country twice the size of Wales (with a population the size of Dorset's). Traffic The capital of Bhutan is Thimphu. It is the only capital city in the world with no traffic lights. When a test set was put in place residents complained because they were too impersonal; within days they were taken down and the traditional method - men in white gloves at either end of the main street - was reinstated. Bhutan had no roads, no electricity, no motor vehicles, no telephones and no postal service until the Sixties. Plastic bags have been banned in Bhutan since 1999 and in 2004 it became the first country in the world to outlaw tobacco. Birthday In Bhutan, all citizens officially become one year older on New Year's Day. The 2003 birthday of the king of Bhutan was celebrated by the inauguration of the country's mobile phone service. The internet was a gift to his subjects from King Jigme Singye to celebrate his Silver Jubilee in 2000. The king abdicated in 2006, nominating his son Jigme Khesar Namgyel to succeed him, as the country's first constitutional monarch. Trouble in paradise In the early Nineties, with a growing Nepalese population alarming the Bhutanese government (neighbouring countries Sikkim and Tibet having been assimilated by India and China), the king decreed that all Bhutanese must follow the strict traditional guidelines of dress and conduct. This led to indignity in the Nepalese community and violence erupted, forcing many Nepalis to flee the country. A resettlement project in the early 2010s saw the repatriation of 40,000 Nepali-Bhutanese to Newark, New Jersey, United States. 1,227 QI Facts to Blow your Socks Off by John Lloyd, John Mitchinson and James Harkin (Faber & Faber, RRP £9.99) is available from Telegraph Books at £9.99 + £1.10 p & p. The new J series of QI is on BBC Two at 10pm on Fridays. The XL version is on Saturdays at 9.10pm