Gurugram, Nov. 26 -- The district's air remained polluted round the year except during the monsoon months, with annual PM2.5 levels more than double the National Ambient Air Quality Standard, according to a latest satellite and ground-based assessment by the Centre for Research on Energy and Clean Air (Crea). The district's annual PM2.5 average stood at 81.27 micrograms per cubic metre based on Central Pollution Control Board (CPCB) data assessed by Crea between March 2024 and February 2025, far above the national safe limit of 40 micrograms per cubic metre. Crea's analysis found that PM2.5 levels dipped close to the national threshold only during the June to September monsoon period when concentrations averaged 44 micrograms per cubic metre. With the end of monsoon, air quality deteriorated sharply in the post monsoon months of October and November, when PM2.5 rose to 119 micrograms per cubic metre, nearly three times the safe limit. "PM2.5 during winter at 95 micrograms per cubic metre and summer at 79 micrograms per cubic metre months never remained in good levels. Once monsoon recedes, the buildup of pollutants in the air continues to remain high in the coming seasons," said Dr Manoj Kumar, analyst at Crea. Using an emission learning model, Kumar said annual average PM2.5 levels in Gurugram at 81.27 micrograms per cubic metre, Faridabad at 80.66, Jhajjar at 76.96, Sonipat at 69.93, Charkhi Dadri at 66.65, Rohtak at 66.03 and Rewari at 64.98 were the highest in Haryana and placed these districts among the fifty most polluted in India. Post monsoon spikes were most severe in Charkhi Dadri at 101 micrograms per cubic metre, Jhajjar at 127, Gurugram at 119, Rohtak at 109 and Sonipat at 120, with fine particulate levels rising between 57 and 84 points in October and November due to stubble burning and Diwali fireworks, experts said.Dr Bharat Gopal, senior director and head of Interventional Pulmonology at Medanta Medicity, said, "Prolonged exposure also accelerates atherosclerosis, elevating the likelihood of heart attacks, stroke, hypertension, worsening of diabetes and certain malignancies particularly lung cancer."Nirmal Kashyap, senior environment engineer at Haryana State Pollution Control Board, said,"Around 1100 additional industrial units have been notified to install mandatory emission monitoring devices by December 31." Gurugram's AQI slipped to the very poor category at 303 on Tuesday. The district ranked 13th among 749 cities in Crea's pollution list, with Faridabad and Jhajjar at 16 and 17....