Greens pledge to launch Senate inquiry into "shameful" asylum seeker policy The Greens have pledged to instigate a Senate inquiry into Australia's "shameful" refugee policy and to introduce national air quality standards, as the party seeks to reconnect with its environmental roots. Greens leader Christine Milne officially launched the party's election campaign by promising the inquiry would scrutinise the legal, financial and moral implications of asylum seeker policy. The cruelty of the "old parties" was "leading us into a legal quagmire and international shame," she said. "There are moments in history when people are so troubled that they search for their nation's soul," she said at the National Convention Centre in Canberra, on Saturday. One such moment is now. At this election we as a people have to chose between the best in us or the worst in us. In her first national campaign launch as party leader, Senator Milne also promised to introduce a Clean Air Act that would set national standards for air quality. Coal trains that pass through populated areas would have to be covered to prevent dust contamination, as part of the proposed law. Much of the rhetoric at the Greens launch focused on the "threat of an Abbott Government." But Senator Milne criticised the two major parties over climate change, same-sex marriage, asylum seekers, higher education funding and environmental protections. "Only the Greens will vote - every single MP and every time - for marriage equality," she said. Ending discrimination matters. It is not a fashion or a fad. She thanked "our very own wise elder" Bob Brown, the former party leader who was in the crowd, for his contribution to the party. Her speech focused on the party's environmental roots, highlighting the risk that the Great Barrier Reef would be added to a list of world heritage sites in danger. She also pointed out that polling day, September 7, was also Threatened Species Day. Senator Milne said the Greens would stand up to the "bullying duopoly" of Coles and Woolworths, while promising a tax cut for small businesses. Recent polls suggest support for the Greens has dropped since the 2010 federal election, when the party recorded its strongest result. Attention has focused on the Greens' only lower house representative, Adam Bandt, who faces a tough fight in the seat of Melbourne. Senator Milne said she was confident Mr Bandt would retain his seat at the election.