The air has finally cleared after a week in which hundreds of wildfires ravaged the Himalayan foothills and the Tarai, shrouding the whole country in smoke. The Air Quality Index (AQI) in Kathmandu spiked to record levels for days on end.
Despite showers on Wednesday and Thursday over parts of the country, the fire calamity is not over yet. Projections show that the concentration of harmful particles below 2.5 microns in Kathmandu will continue to remain at unhealthy levels for another week.
One factor was the extended winter drought, with only 32mm of rain from October-March compared to 177mm, the same period last year in Kathmandu.
“Drought cycles are nothing new but this year we had an exceptionally dry winter, and pre-monsoon is also projected to be dry across the country,” says climate expert Ngamindra Dahal.
The forest floor also had more flammable biomass than usual because last year’s lockdown had prevented villagers from collecting fodder grass and deadwood.
The spring fire season of Baisakh (April-May) has not even started yet, and although the 15mm of rain over the mid-mountains on Wednesday evening helped, we are not out of woods. This is also the season of lightning strikes which could spark off more fires.
The lesson from this year’s record-breaking fires is not to forget about it till next year, but prepare for it by spreading awareness about fires, and dissuading farmers from setting slope alight to allow green shoots to grow for grazing.
The other lesson is that, bad as the smoke haze was, it just made existing urban pollution mainly from vehicle exhaust, worse.
Says atmospheric scientist Arnico Panday: “We have learnt that the absolute worst air quality in cities like Delhi, San Francisco, Sydney or Kathmandu is found when they are importing smoke from large nearby biomass fires. But it is the vehicles and industries that have larger year-around emissions.”
The past week has been a perfect storm of wildfires, vehicle emissions, cross-border industrial pollution, as well as a thick plume of windblown sand dust from the Arabian and Thar deserts. The fires themselves were fanned by strong, up-valley afternoon winds.
The cumulative impact of vehicle exhaust, open burning, and industrial pollution throughout the year is much more harmful to health than a week of smoke, activists say.
Says clean air activist Bhushan Tuladhar: “This week’s forest fires just made the existing air pollution in Kathmandu worse, we should be doing a lot more to reduce vehicular exhaust, brick kilns and open garbage burning.”
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