Delhi-NCR's early-winter air pollution has worsened this year, with the average PM2.5 concentration in the week preceding Diwali touching a three-year high, whi. Construction contributed 7 per cent, while energy use and waste burning accounted for 5 per cent each.The report also pointed out that severe pollution episodes continued even as the contribution of stubble burning declined.Farm fire smoke contributed 3.9 per cent to Delhi's PM2.5 during GRAP Stage I restrictions.