A man walks as other people row boats past flooded streets after Yamuna River overflowed due to monsoon rains in New Delhi on Saturday. Reuters / AFP

The river's levels were at their highest in 45 years this week following unusually heavy rainfall in New Delhi and hilly northern states, forcing the evacuation of hundreds of people as the Yamuna, which runs through the city, breached its banks.

Army and disaster relief personnel were also trying to repair a broken drain regulator near the country's Supreme Court from where water was flowing on to a key road, authorities said.

"To prevent water from flowing into the city, we are trying to create a dam," said Saurabh Bharadwaj, Delhi's flood control and irrigation minister, adding that sacks would be stacked up to achieve this.

Television footage showed water engulfing the walls of the historic Red Fort earlier in the day, with trucks and buses abandoned in several places, leaving just their windshields and roofs showing above the water. Police reported at least three deaths due to drowning.

The roads around the Rajghat memorial to India's apostle of non-violence, Mahatma Gandhi, were inundated too, with some water flowing into the memorial area as well.

With some reduction in water levels in the river, the city resumed operation of one of the three water treatment plants that were closed on Thursday, bringing some relief in supply, Delhi's Chief Minister Arvind Kejriwal said.

At a barrage in the downtown area, army and navy officials were working to reopen five jammed gates that were affecting the flow of the river, Kejriwal added.

Delhi has recorded rainfall 91% above-normal this monsoon season that began June 1. It has received 309mm (12 inches) of rainfall so far in July, which is the third highest for the month for at least 12 years, according to the India Meteorological Department.

Also flooded were several private and government offices, including the police headquarters, in the city's ITO area.

Reuters