2020 saw environment bounce back to its glory, even if temporarily SECTIONS Last Updated: Jan 01, 2021, 04:20 PM IST Share Synopsis According to the Central Pollution Control Board, there was a significant improvement in air quality during lockdown (from March 22 to May 18) as PM2.5 in Delhi reduced by almost 50 per cent as compared to levels observed during 2019. Agencies The pollution level in India's five most-polluted cities - Ghaziabad, Delhi, Noida, Greater Noida and Gurgaon - came down by over 50 per cent during the first 10 days of the lockdown. New Delhi: The COVID-19 pandemic battered and bruised the world in 2020, teaching the value of human life, but an evident positive impact was that it helped the environment bounce back to its glory, even if temporarily.