Indonesia Is Dropping Dry Ice From Planes to Clear Toxic Haze: How It Works

Indonesia is fighting fire from the sky — with frozen carbon dioxide. As toxic haze from land and forest fires spreads across the region, choking cities in Indonesia and neighboring Singapore, authorities have turned to an extraordinary measure: seeding clouds with dry ice to force rain out of the sky. The Guardian reported on Thursday that Indonesia is fighting fire with dry ice as the haze spreads, while the BBC described a country so desperate to clear its skies that it is dousing them with dry ice.

The haze crisis is an annual nightmare. Fires set to clear land for agriculture burn out of control in the dry season, and the smoke drifts across borders — Singapore's Prime Minister Wong has warned of the relentless haze gasping the city-state, according to CNBC. Schools close, flights are disrupted, and millions breathe air thick with hazardous particles. This year, Indonesia decided to attack the problem at its source: make it rain.

How dry-ice cloud seeding works

Dry ice is frozen carbon dioxide, sitting at around minus 78.5 degrees Celsius. When aircraft scatter it through suitable clouds, it supercools the tiny water droplets inside them. The droplets freeze into ice crystals, which grow, clump together and eventually fall as rain — or melt into rain on the way down.

The technique is decades old and has been used worldwide to boost rainfall. What makes Indonesia's use remarkable is the purpose: not watering crops, but drowning fires and washing smoke out of the air. Rain both extinguishes burning land and scrubs particulates from the atmosphere, offering the only fast-acting relief available.

Why it's a desperate measure

Cloud seeding has a hard limit: it cannot create rain from nothing. There must already be the right kind of clouds overhead. If the skies are clear or the clouds are unsuitable, all the dry ice in the world changes nothing. That is why the operation is a gamble — expensive, weather-dependent, and impossible to schedule.

It is also a symptom of a deeper failure. The fires themselves are largely man-made, set deliberately to clear land cheaply, and they return almost every dry season. Cloud seeding treats the smoke; it does nothing about the match. Until land-clearing practices change and enforcement bites, Indonesia will keep finding itself bombing its own skies with dry ice — and hoping for clouds.

What to watch

Meteorologists will be watching whether the seeded clouds actually deliver rain over the fire zones in the coming days. If it works, expect the technique to become a standard emergency tool. If it fails, the haze season will simply run its grim course — and the region will breathe easier only when the rains come on their own.

For more on extreme weather in Asia, read the Budhi Gandaki flash flood in Nepal and the study on who doctors misdiagnose most.

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