Thousands of people were evacuated from their homes in Delhi on Thursday after the authorities warned of widespread flooding following days of torrential rains that have battered large swaths of northern India.

The level of the Yamuna River, which flows through the Indian capital and is a tributary of the Ganges, had breached the so-called danger mark by three meters (about 10 feet) on Thursday, according to the Central Water Commission. That forced the chief minister of the capital region, Arvind Kejriwal, to shut schools and convert them into disaster relief camps.

Many migrant workers, who live on the banks of the river, were camping on the roads alongside it as their makeshift homes were swallowed by the water. Many others were looking for shelter as water enveloped sections of residential areas and historical sites like the Red Fort. So far this monsoon season, officials said, landslides and flash floods have claimed at least 91 lives in six north Indian states near Delhi, and disrupted millions of others.

In the capital, three water treatment plants were shuttered because they were flooded, and many neighborhoods in what is one of the biggest metropolitan regions in the country could face shortages of drinking water.

“Twenty-five percent of the water supply will be affected by this,” Mr. Kejriwal said about the closure of water treatment plants. “People will face difficulties, and they have to bear it. I appeal to the people not to come out of their homes and do maximum work from home.”

Residential areas like the upscale Civil Lines, where Mr. Kejriwal lives, were also flooded.

Mr. Kejriwal, who has faced criticism for failing to prepare the city for heavy rains, said much of the swells in the Yamuna came after federal authorities released water from an irrigation facility upstream from Delhi. The federal government responded by saying it had no choice because the facility was over capacity because of heavy rains.

India has often experienced extreme weather patterns, including record heat waves and heavy floods in monsoon season. Every year, the monsoon brings 80 percent of South Asia’s annual rainfall in a season that starts in June and ends in August. But in recent years, it has become erratic and more extreme, delivering death and destruction through floods and landslides.

So far this season, the hardest-hit area has been the Himalayan state of Himachal Pradesh, where at least 45 people have died since Saturday. The rains have destroyed infrastructure worth millions of dollars there, and in the state of Haryana, thousands of acres of agricultural crops. Tens of thousands of people remain stranded in the state of Uttarakhand, where roads leading to four important Hindu pilgrim sites have been blocked for the last few days.

The following photographs, beginning with one showing flooding near the Red Fort, a 17th-century monument, on Thursday, capture the hardships the heavy rains have wrought.