Delhi recorded a 24-hour average air quality index (AQI) of 395.
Zeta will hit the Louisiana coast as a "significant hurricane," said NHC forecaster Daniel Brown. "Strong winds are likely to spread well inland along the northern Gulf coast this evening and tonight."
Dry weather is expected over the rest of the country during the next four to five days.
The storm was moving northwest at around 9 mph (15 kph) after being nearly stationary over the weekend.
The Ministry of Earth Sciences' air quality monitor, SAFAR, said the wind direction and the wind speed is favourable for the transport of the pollutants from farm fires in Haryana, Punjab, and other neighbouring regions to Delhi.
The direction comes a day after several parts of city, especially south Bengaluru region had faced the brunt of heavy rains as storm water drains overflowed, roads turned into rivulets and many houses were inundated.
Areas like Mundka, Wazirpur and Alipur recorded "severe" levels of air pollution, authorities said.
The city recorded an air quality index (AQI) of 275 at 8:30 am. The 24-hour average AQI was 287 on Saturday. It was 239 on Friday and 315 on Thursday, the worst since February 12 (AQI 320).
The air pollution level in Delhi had hit an eight-month high on Thursday but reduced slightly on Friday with favourable wind speed helping in dispersion of pollutants, even as the contribution of stubble burning to Delhi's PM2.5 concentration rose to 18 percent.
The India Meteorological Department (IMD) said under the influence of a cyclonic circulation, heavy rains are expected over the ghat areas of Maharashtra, Konkan and south Gujarat during the next two days.
Western Maharashtra and coastal districts have been receiving heavy rains since Wednesday resulting in damage to property and lives.
The island city received 106.01 mm rain in the 24-hour period ending at 8 am on Thursday, followed by 69.18 mm rain in eastern suburbs and 58.36 mm in western suburbs during the same period, a Brihanmumbai Municipal Corporation (BMC) official said.
At least 25 deaths were reported in Telangana and Andhra Pradesh on October 14 in rain-related incidents.
The 24-hour average AQI was recorded at 300 at 4 pm, which falls in the poor category. The last time the air quality hit such a poor level was on February 12 when the AQI was 320.
According to the Ministry of Earth Sciences'' Air Quality Early Warning System for Delhi, an increase in farm fires in Punjab, Haryana and neighbouring regions of Pakistan is also going to impact the air quality in Delhi-NCR.
Under its influence, very heavy rainfall is expected over Telangana, heavy to very heavy falls at isolated places are likely over Karnataka, Rayalaseema, south Konkan and Goa, central Maharashtra and Marathawada on Tuesday, the Cyclone Warning Division of the IMD said.
Improving technology could make it possible to better anticipate weather conditions weeks in advance, especially in the tropics.
Conditions are becoming favourable for its further withdrawal from some more parts of Rajasthan and Punjab and some parts of Haryana, Chandigarh, Delhi, Uttar Pradesh and Madhya Pradesh during next two to three days, the IMD said.
Overall, the country has received 9 percent more rainfall than normal until September 26, according to data.
The northwest meteorological division of IMD comprises Rajasthan, Uttar Pradesh, Himachal Pradesh, Uttarakhand, Punjab, Haryana and the Union territories of Chandigarh, Delhi, Jammu and Kashmir and Ladakh. Almost all states have recorded a large deficiency from September 1-23.
Yellow alert was issued with a forecast of heavy rain at isolated areas or thunderstorms accompanied by lightning and gusty winds for September 21
The India Meteorological Department (IMD) has issued a red alert in Idukki, Thrissur, Palakkad, Malappuram, Kozhikode, Wayanad, Kannur and Kasaragod districts on Sunday.
Several parts of central and south India are likely to receive heavy rainfall in the next two days. The IMD has also issued orange warning for Kerala, Goa and parts of Karnataka and Maharashtra on Saturday.
Mississippi and Louisiana issued mandatory evacuation orders to residents of low-lying areas, and Louisiana Governor John Bel Edwards appealed for a federal disaster declaration and advised people living in Sally's path to flee.
Every year, Pakistan struggle to cope with the annual monsoon deluge and other rain-related incidents which cause huge loss of life and properties. The monsoon season runs from June-July through September.