Delhi and Lahore Choke Under Smog as Diwali Nears, With Delhi Ranked Worst Worldwide

Two of South Asia’s biggest cities woke up to dangerous air on Saturday. Swiss monitoring group IQAir placed Delhi first among major cities worldwide, while Lahore in Pakistan also showed a severely unhealthy reading. At 10:35 a.m. local time, Delhi’s US air quality index was 581 and Lahore’s was 285. That means the Indian capital’s number was roughly double its neighbor’s, yet Lahore’s level still signals a serious risk for residents.

Lahore Pollution Level Compared With Delhi

What the Numbers Mean

IQAir’s index is built on measured pollutant concentrations, so it cannot be compared directly with India’s official scale. India’s Central Pollution Control Board put Delhi at 363 at 10 a.m., which falls in the very poor category. Local media said Friday brought the worst pre-Diwali air in eight years.

Why Lahore and Delhi Suffer Every Winter

Northern India and nearby regions face this problem each year as cold weather arrives. Heavy, cool air traps vehicle fumes, construction dust and smoke from crop waste burning close to the ground.

Diwali falls on Sunday, and the festival of lights is usually marked by widespread firecracker use, which pushes pollution higher still. Authorities have asked schools in and around Delhi to switch to online classes and encouraged people to work from home.