On Hero Cycles-NDTV #TheCycleOfChange telethon, Sunita Narain, Director General, Centre For Science And Environment highlighted that the past days of lockdown have provided the evidence that combustion from vehicles and industries are the biggest source of air pollution. She said that the dramatic difference in air quality is because the polluting agents are not functioning and therefore after the lockdown is lifted major steps need to be taken to maintain the air quality.