Delhi: AQI between zero and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", and 401 and 500 "severe". December 2023 was the national capital's warmest month in six years, with the city not recording a single 'cold wave day' during the month, the IMD said.
