New Delhi, Nov. 7 -- Air pollution levels in Delhi surged by more than 100 points on the air quality index (AQI) on Thursday as smoke from farm fires in Punjab and firecrackers burst overnight in the capital combined with local emissions trapped by calm winds and falling temperatures to shroud the city in thick haze. The AQI stood at 311 in the "very poor" category at 4 pm, up from 202 a day earlier, when people in several parts of the city illegally burst firecrackers to celebrate Gurpurab. The grey haze that descended late on Wednesday persisted through Thursday morning, a stark contrast to the visually cleaner blue sky just a day earlier, as pollution made eyes water and throats scratchy. Stubble burning in other states contributed an estimated 9.48% to Delhi's PM 2.5 pollution on Thursday - the highest so far this winter - with forecasts showing the share could surge to 38% by Friday as northwesterly winds continue transporting smoke from agricultural fires, according to the Centre's Decision Support System (DSS). The current period is among the most acute for the Capital's annual winter air pollution crisis, when calm local winds, dropping temperatures and smoke from crop residue burning converge to create a public health emergency. Past data shows stubble fires typically peak in the first week of November, with single-day contributions reaching 35% last year and as high as 48% in 2021. Prior to Thursday, the highest stubble contribution this season was 5.87% on October 28. Weekend forecasts show the contribution declining slightly to 25.3% on Saturday and 31.76% on Sunday as stronger northwesterly winds provide some dispersion, though these winds are also responsible for the long distance transport of stubble fire smoke....