The National Green Tribunal (NGT) has expanded its ambit in air pollution cases to cities beyond Delhi. The green panel yesterday directed states to file a comprehensive affidavit stating the steps taken by them for prevention and control of air pollution.<br/><br/>Restrained by the Supreme Court from dealing with matters on air pollution in Delhi, NGT took note of the pollution in other cities like Mumbai, Kolkata, Bangalore, Chennai, Hyderabad and Amritsar.<br/><br/>A bench, headed by NGT Chairperson Justice Swatanter Kumar, also asked the state pollution control boards to take air quality samples in major cities across India and submit the analysis reports before 9th of next month.<br/>In contrast to the prior NGT order banning registration of all diesel vehicles in Delhi, the Supreme Court had on the 16th of last month exempted small ones from the ban.