Bhopal gas leak victims, demanded immediate scientific assessment of environmental pollution caused by the tragedy three decades back on Sunday...Social activist Satinath Sarangi, who has been working for the victims, says that a scientific assessment of air, water and ground quality should be done to address the situation...Activists want this waste removed and disposed of away from the area, and feel Indian authorities, who now own the site, have fumbled on taking action - either by clearing up the waste itself or in pursuing Union Carbide to take responsibility...as US President Barak Obama will visit India for Republic Day celebrations in January, activists say the American government should apologise and demand extradition of John Macdonald, secretary of Union Carbide.