Kathmandu, April 23 -- The air quality in Kathmandu has deteriorated sharply in the last 24 hours, with the city ranking as the second most polluted in the world, according to data released by IQAir.

The Air Quality Index (AQI) in Kathmandu was recorded at 247, placing it just behind Lahore, Pakistan, which topped the global list with an AQI of 381. An AQI level above 200 is considered very unhealthy and poses serious health risks to the general population.

PM2.5 refers to particulate matter (solid or liquid droplets) in the air less than 2.5 micrometres in diameter. It is among the most dangerous pollutants that can get past the nose and throat to penetrate the lungs and even the bloodstream. PM2.5 particles are small and are also like...