Delhi’s air quality remains “very poor” as firecrackers push PM2.5 beyond 50x WHO limits in parts of Delhi on Deepavali night. According to an analysis by the Centre for Research on Energy and Clean Air (CREA), 36 out of Delhi's 59 air quality monitoring stations were not reporting data by 1 am on Monday. DPCC's Diwali-night data shows Delhi's PM2.