Residents in India's northern states woke up to another day of poor air quality on Tuesday, as a layer of dense fog shrouded most of the region, and pollution in the capital Delhi remained severe.

India battles air pollution every winter as cold, heavy air traps dust, emissions, and smoke from farm fires started illegally in the adjoining, farming states of Punjab and Haryana.

The air quality index (AQI) touched a peak of 491 in Delhi on Monday, forcing the government to introduce restrictions on vehicle movement and construction activities, and schools to conduct classes online.

On Tuesday, Delhi's 24-hour air quality index (AQI) reading was at 488 on a scale of 500, India's Central Pollution Control Board (CPCB) said, and at least five stations in the capital reported an AQI of 500, Retuers reported.

CPCB defines an AQI reading of 0-50 as "good" and above 401 as "severe", which it says is a risk to healthy people and "seriously impacts" those with existing diseases.

Swiss group IQAir ranked New Delhi as the world's most polluted city with air quality at a "hazardous" 489, although that was a significant improvement from Monday's 1,081 reading.

Experts say the scores vary because of a difference in the scale countries adopt to convert pollutant concentrations into AQI, and so the same quantity of a specific pollutant may be translated as different AQI scores in different countries.

India's weather department said a shift in the fog layer towards the northern state of Uttar Pradesh had helped improve visibility over Delhi.

Visibility dropped to zero metres in Uttar Pradesh's capital Agra, which lies southeast of Delhi. The Taj Mahal, India's famed monument of love, has been obscured by toxic smog for nearly a week.

The strict measures to mitigate the impact of high pollution have hurt production at more than 3.4 million micro, small and medium enterprises in the nearby states of Punjab, Haryana and Delhi, local media reported.

Pakistan's Punjab declared a health emergency due to toxic smog on Friday, banning construction, shutting schools for another week and moving universities online, with a three-day lockdown possible, the province's senior minister said on Friday.

Punjab battles toxic smog every winter as cold air traps dust, emissions, and smoke from illegal stubble burning on fields. Air quality has deteriorated drastically in recent weeks and the province's capital Lahore currently ranks as the world's most polluted city, says IQAir.

"A complete lockdown will be enforced on Friday, Saturday, and Sunday (next week) if the situation does not improve by Wednesday," said Punjab Senior Minister Marriyum Aurangzeb, addressing a press conference in Lahore.

Citizens were advised to stay indoors. Air Quality Index (AQI) readings in Lahore reached 637 at 3 p.m. (1000 GMT), according to Swiss group IQAir, significantly higher than levels recommended by the World Health Organization.

The government had ordered the closure of construction, brick kilns, and furnace-based plants in Lahore and the city of Multan, the minister said.

Punjab's government had last week ordered schools to close until Nov. 17, and on Friday the shift to online learning was extended for another week. Colleges and universities will also shut down, moving to virtual classes.

The eastern province has already banned entry to parks, zoos, playgrounds and other public spaces.

South Asia faces severe pollution each year due to trapped dust, emissions and stubble burning - the practice of setting fire to fields after the grain harvest.

Punjab has blamed this year's particularly high pollution levels partly on toxic air flowing from neighbouring India, where air quality has also reached hazardous levels.

India's capital of New Delhi, the world's most polluted capital city, banned all non-essential construction, moved younger children to virtual classrooms and asked residents to avoid using coal and wood from Friday to combat increasing air pollution.

New Delhi's air quality level reached 539 on Friday, according to live rankings by IQAir, the worst amongst global capitals.

Sher Mohammad Abbas Stanikzai, the political deputy of the Ministry of Foreign Affairs, on Monday called on industrial countries to help Afghanistan in the fight against climate change.

Stanikzai made the remarks at a conference in Kabul titled “From Isolation to Inclusion – Afghanistan’s Urgent Call for Climate Action,” which was held on the day the UN climate talks kicked off in Azerbaijan’s capital Baku.

"Our demand from the United Nations, the great powers, the rich countries and the countries from which gasses come is to help us improve our environment and serve our people," Stanikzai said.

Stefan Rodriguez, the Chief of the United Nations Development Programme (UNDP), also said that climate change has forced some Afghans to live in tents as natural disasters regularly occur in the country.

Rodriguez, however, said that after three years, Afghanistan has now gained access to financial mechanisms in the environmental sector and some institutions are ready to resume their incomplete projects in Afghanistan.

The organizers of the conference warned that if the international community does not step up to assist Afghanistan in the fight against climate change, there will be dire consequences.

They called on COP29 in Baku to keep the issue of fighting climate change in Afghanistan away from political issues and work with their financial and technical partners to prevent the spread of negative effects of climate change in the country.