The air quality index (AQI) of Lahore has once again surged past the 300 mark, the threshold considered “hazardous” for human health despite continuous efforts of the provincial authorities to bring down smog levels in the Punjab capital. The increase in the AQI value occurred for the first time in nearly three weeks as the city was last seen in the “hazardous” range on November 28, as per the Swiss air quality monitor’s graph. As per IQAir, Lahore ranked second in the world rankings of most polluted cities in terms of air quality on Tuesday, with an AQI value of 532, while Indian capital New Delhi topped the list with a whopping AQI value of 800 around 10:34am. Lahore has mostly been shrouded in thick smog since beginning of the winter season with registering extremely high levels toxins in the atmosphere for weeks. However, drastic measures by the government including partial lockdown apparently gave the city a brief respite before its air quality rebounded to toxin level today. The city, home to its 14 million residents, has been facing the brunt of the worsening smog crisis that continues to engulf the province prompting authorities to take extraordinary measures to fight off smog. The crisis hits the most populous province of the country every winter, but air pollution has worsened in the recent years, as a result of cold air trapping dust, low-grade diesel fumes and smoke from illegal stubble burning on fields. The authorities have blamed the intensifying pollution crisis in Punjab on neighbouring India, where the capital city New Delhi remains on top of the list among worst air qualities. As cold weather sets in in Karachi as well, the metropolis’ air quality also deteriorates. Today, the port city held the fifth spot in the IQAir’s list, with an AQI value of 200, a level considered “unhealthy” for humans.