New Delhi, Feb 2 (IANS): Delhi's air quality remained in the "very poor" category for fourth day in a row on Saturday and no respite is likely in the next few days, said experts, warning that it may marginally deteriorate further on Sunday and that an improvement is unlikely until Tuesday.

System of Air Quality and Weather Forecasting and Research (SAFAR) said the little amount of shower experienced in the past few days had become a stumbling block for dispersion of pollutants in spite of not-so-calm surface wind conditions.

The agency said these showers had introduced huge amount of moisture to make air heavy with drops in temperature, a circumstance that makes dispersion difficult.

"This process is balancing the air pollution level and keeping it consistently in the lower end of 'very poor' range. However, by Sunday, wind speed is expected to slow down and at the same time, temperature is likely to increase to make foggy conditions better.

"As a result, air quality will slightly deteriorate by tomorrow...will remain in very poor range for next two days and then start to improve," it said.

The overall Air Quality Index (AQI) of Delhi was recorded at 322 (very poor) on Saturday, which is expected to deteriorate further to 333 on Sunday.

In the National Capital Region, Noida and Gurugram also experienced sustained "very poor" air quality.

The SAFAR warned sensitive groups to avoid all physical activity outdoor and move activities indoors.

"If asthematic, keep relief medicine handy."

To others, it recommended stopping outdoor activity at early morning and after sunset times and avoid prolonged or heavy exertion.

"Go for a short walk instead of a jog and take more breaks. Stop any activity level if you experience any unusual coughing, chest discomfort, wheezing, breathing difficulty, or fatigue," it advised.

"Avoid burning of wood, candles or incense. Keep the room clean -- don't vacuum. Do wet mopping to reduce dust."