New Delhi: With the odd-even scheme set to return from April 15, the government today played down its impact on air pollution, saying a single factor or action cannot substantially reduce pollution levels in the national capital.

Environment Minister Prakash Javadekar, in a written reply in Lok Sabha, said a comprehensive set of actions following an integrated approach is required to make substantial improvement in air quality. He said the Central Pollution Control Board (CPCB) had assessed the impact of odd-even scheme launched by Delhi government from January 1-15 this year.