Gurgaon: Air quality in the city worsened to ‘moderate’ category on Thursday, with Air Quality Index (AQI) rising to 101 from 82 on the previous day.On Wednesday, carbon monoxide was the main pollutant. “This is different from the city’s usual pattern, where particulate matter is the primary contributor,” experts said, adding that the higher share of carbon monoxide points to local sources such as vehicle emissions and incomplete combustion, rather than dust or regional factors.Officials said this reflects changes in the city’s pollution pattern as summer begins. “When carbon monoxide drives AQI levels instead of particulate matter, it usually indicates the impact of traffic congestion, fuel combustion and other near-ground sources. Such pollution is often more concentrated in densely populated and high-traffic areas,” an expert said.Data from the four continuous ambient air quality monitoring (CAQM) stations showed variation in pollution levels across the city. Sector 51 and Vikas Sadan recorded higher AQI levels of 120 and 130 respectively, placing them in the ‘moderate’ category. Stations closer to the Aravali foothills, NISE Gwal Pahari and Teri Gram, reported better air quality with the levels falling in the ‘satisfactory’ category and reaching 70 and 59, respectively.Experts said lower pollution levels in the Aravali areas are due to better green cover, lower traffic and improved dispersion. “In contrast, central sectors and densely populated areas remain more affected by vehicle emissions, especially during peak traffic hours when pollutants tend to stay close to the ground,” an expert said.Meanwhile, an analysis of AQI trends over the past week shows a brief rise followed by stabilisation. “The absence of dust-laden winds and relatively favourable dispersion conditions have helped keep air quality in check,” an HSPCB official said.According to CPCB guidelines, sustained exposure to ‘moderate’ category air can cause breathing discomfort for people with asthma and heart or lung disease. An AQI between 0 and 50 is classified as ‘good’, 51 to 100 ‘satisfactory’, 101 to 200 ‘moderate’, 201 to 300 ‘poor’, 301 to 400 ‘very poor’ and 401 to 500 ‘severe’.With temperatures expected to rise further in the coming days, dispersion may improve. However, experts said local sources of pollution will continue to influence the city’s air quality, highlighting the need for regular monitoring as summer approaches.
