Falling mercury and low wind speed have left the Capital freezing and choking. The air quality in the national capital continued to remain in the ‘severe’ zone for the second consecutive day on Wednesday and is likely to stay there for the next few days. IMD has said that there is a possibility of marginal improvement in wind speed from December 25, which may bring down the high levels of pollution. Meanwhile, the temperature will also continue to drop over the coming days in Delhi and the neighbouring cities. On Wednesday, the minimum temperature was recorded at 4 degrees in the Capital.