On Saturday, a haze had engulfed the national capital and the worst air quality of this season was recorded at 324. Anumita Roychowdhury of Centre for Science and Environment (CSE) Monday said, as winter approaches, toxic air emanating out of such landfill fires is likely to affect the air quality. An AQI between 0 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. 

If the wind speed is lower and the temperature dips, the polluted air coming out of landfill fires will get trapped, which would severely affect the air quality," she said.. The Supreme Court-appointed Environment Protection Control Authority (EPCA) had last week held a meeting with officials of Punjab, Haryana and the Delhi governments to discuss the pollution situation in the national capital. On Sunday, the AQI had oscillated between poor and very poor categories. The fire was extinguished Monday by a team of firefighters even as the areas civic body said it was keeping a watch on it, while Delhi Environment Minister Imran Hussain directed the municipal corporation to work on preventing landfill site fires. The Centre-run System of Air Quality Forecasting and Research (SAFAR) also reported an AQI in the poor category.The Central Pollution Control Board (CPCB) recorded the citys overall AQI at 252 at 11 am.New Delhi: Delhis air quality continued to be in the "poor" category Tuesday, a day after it had improved from "very poor" Air Quality Index (AQ1) zone. The air quality in the national capital had shown signs of improvement Monday as it China Commercial Air Conditioners moved from very poor to poor category, but experts said it could deteriorate in the coming days due to toxic air coming out of a fire at Bhalswa landfill site