Delhi is in danger of losing the gains of its CNG programme as pollution levels are once again creeping up to pre-2000 level. A latest analysis of recent air quality data in Delhi carried out by the Centre for Science and Environment (CSE) finds that pollution levels are on the upswing again after a few years of control. Last winter, for the first time, pollution levels increased and this year pollution levels are already almost as high as what was in the city in pre-CNG days. Says Sunita Narain, director, CSE: “We will have to take tough measures to control growing air pollution and fast. Otherwise, Delhi will find itself in the choked and toxic haze of the pre-CNG days, when diesel-driven buses and autos had made it one of the most polluted cities on earth.”