Delhi grappled with a cold wave on Tuesday as the minimum temperature at the Safdarjung Observatory, considered the official marker for the capital city, settled at four degrees Celsius, four notches below normal.

On Monday, the national capital had recorded a low of 3.2 degrees Celsius, five notches below normal and the lowest so far this season.

Though there was a marginal rise in the minimum temperature, it was still on the lower side, as the weather remained chilly in the morning.

The relative humidity was recorded at 94 per cent, according to the India Meteorological Department.

In the plains, the IMD declares a cold wave if the minimum temperature dips to 4 degrees Celsius. A cold wave is also declared when the minimum temperature is 10 degrees Celsius or below and is 4.5 notches below than normal.

The weather office has forecast shallow fog in the day and the maximum temperature is likely to hover around 21 degrees Celsius.

Two back-to-back Western Disturbances and the resultant slowing down of cold northwesterly winds from Tuesday night will push the minimum temperature up, R K Jenamani, a senior scientist at the IMD, had said on Monday.

Cold wave conditions were observed on Tuesday at a few places over Haryana, Madhya Pradesh, Jharkhand, Odisha, and at isolated pockets over Punjab, Delhi, Uttar Pradesh, Rajasthan, Chhattisgarh, Bihar, Gangetic West Bengal, Saurashtra and Kutch, Vidarbha and Telangana, official said.

The air quality index of Delhi in the morning was 380, which falls in the very poor category, according to CPCB data.