Toxic foam covers one of India's most sacred rivers putting millions of Hindus at risk

One of India’s most sacred rivers, the Yamuna in New Delhi, is covered in white toxic foam.

The pollution puts millions of residents at risk as the river provides more than half of the Indian capital's water and Hindu devotees bathe in it, believing the body of water to be sacred.

The foam has formed from pollutants dumped by industries around the city.

'I worship the river as a mother'

Jasraj, a 70-year-old retired government clerk, said he has been visiting the river for a bathing ritual since 1980.

"I worship the river as a mother, and there is no question of its being clean or dirty. It's dirty on the surface but clean below the top," he said.

The 1,376-kilometer Yamuna is one of the holiest rivers for Hindus. It is also among the most polluted in the world. Dangerously unhealthy waterways are a concern for many, especially with pollution expected to worsen during the upcoming Chhath Puja, a Hindu festival.

During the festival, thousands of Hindus are expected to stand knee-deep in the Yamuna's frothy, toxic waters, sometimes even immersing themselves in a holy dip to mark Chhath Puja.

The river has become dirtier over the years as sewage, farm pesticides and industrial effluents flow into the waterway despite laws against polluting and authorities setting up dozens of sewage treatment plants.

The New Delhi government said officials were using defoamers to tackle the problem. Authorities have deployed dozens of motorboats to disperse the foam and erected bamboo barricades to keep people away from the river banks.

How did New Delhi become one of the most polluted places on Earth?

New Delhi also has some of the world’s most polluted air every year, and the current festival season is exacerbating the situation.

On Tuesday, the air-quality index deteriorated to a 'very poor' reading of 273, 18 times higher than the World Health Organization’s recommended levels. The tiny PM 2.5 particulate matter can enter deep into the lungs and cause diseases.

Imran Khan, a student, said it's difficult to breathe properly in Delhi's polluted air.

"People are here for jogging, and they are facing problems, too. Our environment should be cleaner," he said.

Winters, in particular, have become a time of health woes in India’s capital, which is home to more than 20 million people. During winter the city is covered with a toxic haze that obscures the sky.

Pollution levels soar as millions of Hindus celebrate Diwali, the festival of light, amid emissions from massive firecrackers. Diwali will be celebrated on Thursday.

Farmers in neighbouring agricultural regions also set fire to their land after harvests to clear it for the next crop season.

India's Supreme Court earlier this month slammed northern Indian states for not taking stricter action against people burning crop residues ahead of the winter season and aggravating the region's air pollution.

Every year, authorities shut construction sites, restrict diesel-run vehicles and deploy water sprinklers and anti-smog guns to control the haze and smog enveloping the skyline of the capital region.