Lahore's air ranks worst on Earth as Delhi clamps down on smog

Lahore woke up on Nov 3 choking on the dirtiest air on the planet. The city's air quality index hit 447 early in the day, according to IQAir, the Swiss outfit that tracks toxins in the sky. Anything up to 50 is considered safe. Lahore blew past that by a mile.

The finer numbers are uglier still. Lahore's PM2.5 concentration ran 60 times higher than the World Health Organization's annual exposure guideline, per IQAir. Those are the tiny particles that slip into the lungs and are linked to deadly disease and heart trouble. Authorities blame a sharp drop in temperatures and sluggish winds for trapping the filth in place.

Pakistan isn't sitting still. The government has cranked up enforcement against brick kilns breaking environmental rules and keeps pressing farmers to stop torching crop residue after harvest. Neither problem disappears overnight in a region where cold, dense air acts like a lid on vehicle fumes, construction dust and burning fields.

Delhi's numbers look gentler on paper, but only by comparison. IQAir put the Indian capital at 215, while India's Central Pollution Control Board rated it 'very poor' with a reading of 332. The two agencies use different scales and methods, which explains the gap. Either way, the air is bad enough that Delhi's graded control measures kicked in on Nov 2, targeting polluting vehicles, construction activity, coal and firewood in eateries, plus more public transport.

Fireworks season looms over all of it. Diwali celebrations are expected to pile more smoke onto the haze, so India's Supreme Court has limited the capital to low-polluting fireworks for three hours each on Nov 7 and 8. This is the same pre-winter trap the region falls into every year, pushing pollution to the highest levels in the world and putting millions of residents at serious respiratory risk.