10 min read · Global Air Quality
The scale of the problem
Many of the world's most polluted cities are in South Asia. In Delhi and across the Indo-Gangetic Plain, fine particle (PM2.5) levels in late fall and winter regularly reach many times the World Health Organization's guideline of 5 µg/m³ annual average, and "severe" AQI days are common in November.
What causes it
- Crop-residue burning in Punjab and Haryana after the rice harvest.
- Vehicle exhaust from rapidly growing traffic.
- Industry and power plants, including coal.
- Construction and road dust.
- Household fuels – wood, dung and coal for cooking and heating.
- Festival fireworks around Diwali.
- Weather: cold, still winter air creates temperature inversions that trap pollution near the ground.
Health effects
Long-term exposure to PM2.5 is linked to asthma, lung disease, heart attacks, strokes and reduced lung development in children. Studies estimate that air pollution shortens average life expectancy in the most affected regions by several years.
How people protect themselves
- Well-fitted N95/FFP2 respirators outdoors.
- HEPA air purifiers at home, especially in bedrooms.
- High-efficiency (MERV 13+) filtration in buildings with central air.
- Checking the AQI daily and limiting outdoor exercise on bad days.
Why it matters to Canadians
Canada's air is generally among the cleanest in the world, but wildfire smoke now pushes some Canadian cities to similar short-term pollution levels. Many Canadians also travel to or have family in South Asia. The same tools – respirators, HEPA purifiers and good HVAC filters – work in both places. See our Wildfire Smoke Survival Guide.
Clean air starts with the right filter. Shop MERV 13 and HEPA filters, made in Brampton, Ontario.