Bhopal gas tragedy survivors now threaten to stop trains passing through the city from December 3, the 27th anniversary of the world's worst industrial disasters. Denied proper compensation, they must now even contend with the tainted Dow Chemical's retaining sponsorship for London Olympics 2012. In fact on Friday, hundreds of agitated protestors and victims of the 1984 Bhopal gas tragedy demonstrated their anger. Activists and victims marched with banners, anti Dow Chemicals tableaus on the streets of Bhopal and shouted slogans.