The monthly average AQI stood at 223 in October 2025, 234 in 2024, 219 in 2023, 210 in 2022, 173 in 2021, 265 in 2020, 234 in 2019 and 269 in 2018, according to a statement issued by the ministry. Delhi recorded an average Air Quality Index (AQI) of 166 in October, the lowest monthly average for the period in eight years, the Union Environment Ministry said on Saturday.