An assessment by the Centre for Research on Energy and Clean Air (CREA) found that most National Capital Region (NCR) cities breached India's annual PM2.5 air quality standards in 2025. Delhi was identified as the most polluted city in NCR and among major Indian metros. The analysis, based on CPCB data, indicated that all monitoring stations in Delhi exceeded the annual PM2.5 standard, with concentrations at least 1.8 times the permissible limit. Ghaziabad recorded the highest number of days breaching the daily PM2.5 limit.