Delhi tests water cannons to combat deadly air pollution

A water mist cannon, or "anti-smog gun," gets a tryout this week in New Delhi to reduce air pollution.

Story highlights

  • A machine sprays atomized water up to 230 feet into the air
  • It aims to merge with dust particles and replicate effects of rain to lower pollution level

New Delhi (CNN)As it grapples with toxic smog, the Delhi government has turned to an unusual solution to tackle its air pollution problem.

Water mist cannons, or "anti-smog guns," have been tested in Anand Vihar, an area in northern Delhi that's one of the Indian capital's most polluted regions.
A machine is connected to a water tank and mounted on a flatbed truck and sprays atomized water -- in which liquid is broken up into smaller droplets -- up to 230 feet into the air.
    The idea is that the droplets merge with dust particles, replicating the effect of rain. Rain lowers levels of air pollution by bringing particulates in pollution down to the ground.
    In 2015, use of the machines was widely reported in China, and they could soon become a familiar site on the streets of Delhi.
    A daylong trial was carried out Wednesday by the Department of Environment and the Delhi Pollution Control Committee, part of the city's governing Aam Aadmi Party.
    Delhi Environment Minister Imran Hussain, who witnessed the tests, told CNN affiliate News 18 that "the idea came about in a series of meetings, where even helicopters sprinkling water on the city were suggested."
    If the trial is successful, the machines will be used across the city when pollution levels rise, according to Hussain.

    'Systemic changes' advocated

    But many remain skeptical of this solution.
    "These only work in a very local situation like a construction site, if you want to douse the dust, then you do this for an immediate and instantaneous effect, but this is not what you would use to control air pollution," Anumita Roychowdhury of the Delhi-based Centre for Science and Environment think tank told CNN.
    Pollution control measures should give you sustained improvement over time, she said. "The government needs to focus on systemic changes, infrastructural changes so that they can effectively control pollution across the city."
    Known as the Fog Cannon, the machines are made by Cloud Tech, an Indian firm based in Haryana state, which borders Delhi.
    On Cloud Tech's website, the company says the Fog Cannon is designed to "tackle the problem of airborne dust particles generated by open mining activities, demolition work and bulk material handling" as well as localized sources of dust, as highlighted by Roychowdhury.

    Among the world's worst

    Delhi's poor air quality is ranked among the world's worst, with some parts of the city reporting levels almost five times those considered "unhealthy" by the US Environmental Protection Agency.
    Air quality measurements provided by the Delhi Pollution Control Committee track smog levels across the city in real time.
    Those levels are based on the concentration of fine particulate matter, PM2.5, per cubic meter. The microscopic particles, which are smaller than 2.5 micrometers in diameter, are considered particularly harmful because they are small enough to lodge deep into the lungs and pass into other organs, causing serious health risks.
    The World Health Organization considers a PM2.5 density above 25 micrograms per cubic meter within a 24-hour period as unsafe. In Delhi, an "emergency" level is anything above 300. In November, when a white haze descended on the city, levels topped 1,000 at one point.
    The situation is aggravated by Delhi's geography.
    The landlocked city sits in a natural bowl and is surrounded by industrial and agricultural hubs.