Amnesty International on Friday issued an "urgent action" warning for the hazardous smog that has been engulfing Lahore, saying every resident of the city is at risk due to the poor air quality.

The unprecedented step is aimed at mobilising supporters around the world to campaign on behalf of Lahore's population to seek relief from the authorities, the NGO said in a press release.

Lahore topped the list of the world's most polluted cities for the second consecutive day on Friday. Around 8am, the city's air quality was recorded by Air Visual to be 385, which is classified as 'unhealthy'. The Punjab government, for the third time this month, announced the closure of schools due to "dense smog" in three districts, including Lahore, Faisalabad and Gujranwala.

“The government’s inadequate response to the smog in Lahore raises significant human rights concerns. The hazardous air is putting everyone’s right to health at risk,” said Rimmel Mohydin, South Asia campaigner at Amnesty International.

“The issue is so serious that we are calling on our members around the world to write to the Pakistani authorities to tell them to stop downplaying the crisis and take urgent action to protect people’s health and lives.”

'Urgent Actions' are a campaigning tool that Amnesty International uses to mobilise support internationally for victims of human rights violations and for prisoners of conscience.

The organisation noted that for one in every two days this month, the air quality in Lahore has been classified as “hazardous” by air quality monitors installed by the United States Consulate in Lahore and the Pakistan Air Quality Initiative. The situation also forced the provincial government to shut schools down on three occasions this month.

The Air Quality Index (AQI) in Lahore reached 580 at 11pm on November 7. Since the beginning of the month, at least seven days have seen air quality reach hazardous levels.

"Lahore has not had a single day of healthy air this year," Amnesty said, citing information from the Pakistan Air Quality Initiative, a citizen-led effort that crowdsources and collates data on air quality.

It noted that in view of the alarming situation, a group of teenage students earlier this month filed a suit against the Punjab government in the Lahore High Court for the “violation of their fundamental right to a clean and healthy environment”.

In the petition, the three students said the government had been downplaying the scale of crisis because its standards of measurement differ from the ones used in other countries and accepted internationally.

“Today, people are not aware of just how much danger they are in because of the air they breathe. If the expertise is available, if the consequences are dire, if the evidence of the damage is mounting, then the government must not waste time.

“A good starting point would be to acknowledge the risks of the quality of air and initiate smog protection protocol as recommended by the court-appointed Smog Commission,” said Mohydin.

For the last four years, smog, rightly being called the fifth season of Lahore, has deprived the people of sunshine and dusk-hour charm as layers of toxic smoke engulf the horizon from November to February.

The situation became worse this year as the Punjab government, for the first time, announced the closure of schools due to dense smog. Residents accuse the government of taking insufficient measures to control the situation even as the administration insists that it is making efforts to deal with the smog.

Government officials blame the smog on crop burnings in India. Experts, however, say that the situation is caused by pollution in the country.