According to the Central Water Commission's data, the water level in the Yamuna dipped from 206.59 metres at 7 am on Wednesday, the highest since August 2019, to 205.37 metres at 9 am on Thursday.It is likely to drop below the danger mark of 205.33 metres during the day.?

The city administration had issued a flood alert, suspended rail traffic movement on the Old Yamuna Bridge?and evacuated around 6,500 people from low-lying areas close to the Yamuna on Tuesday as the river breached the evacuation mark of 206 metres following a late spell of heavy rain in the upper catchment areas, especially Uttarakhand and Himachal Pradesh, last week.??

Since there has been no significant rainfall in the upper catchment areas over the last to three days, the water flow rate from Haryana's Hathnikund Barrage has also come down from?96,000 cusecs at 7 am on Tuesday to?25,400 cusecs at 9 am on Wednesday and further to 17,800 cusecs at 9 am on Thursday.

One cusec is equivalent to 28.32 litres per second. Normally, the flow rate at the Hathnikund barrage is 352 cusecs, but the discharge increases after heavy rainfall in the catchment areas. The water discharged from the barrage normally takes two to three days to reach the national capital.

Officials said civil defence workers deployed in the affected low-lying areas are asking people not to move back to their houses till the water recedes to the normal level.?The low-lying areas near the river in Delhi are considered vulnerable to flooding and are home to around 37,000 people.

Most of the people shifted to safer places themselves. The Delhi administration had to evacuate around 6,500 people and move them to community centres, schools and temporary tents, an official said. "We expect the water to recede to normal levels in two to three days. Thereafter, these people can go back to their places," he said.

Though the land along the Yamuna belongs to the Delhi Development Authority, Revenue Department and private individuals, encroachments have come up on a large part of the river floodplains over the years.?Normally, flooding in the Yamuna is reported in July or August which receive maximum rainfall during the monsoon season.?

Also, this was the second time within two months that a swollen Yamuna inundated low-lying areas in Delhi, forcing people to shift to safer places. The Yamuna had breached the danger mark of 205.33 metres on August 12, following which around 7,000 people were evacuated from the low-lying areas near the riverbanks.

The water level had shot up to 205.99 metres on August 13 before the river started receding. The catchment of the Yamuna river system covers parts of Uttar Pradesh, Uttarakhand, Himachal Pradesh, Haryana, Rajasthan, Madhya Pradesh and Delhi.

The river enters Delhi at Palla in the north district and traverses a length of 48 km through central, northeast, Shahdara, east and southeast Delhi before leaving at Jaitpur. Last year, the Yamuna breached the danger mark on July 30 and the water level at the Old Railway Bridge rose to 205.59 metres.

In 2019, the flow rate had peaked at 8.28 lakh cusec on August 18-19, and the water level in the river had hit the 206.60-metre mark. In 1978, the river had swollen to the all-time record water level of 207.49 metres. In 2013, it had risen to 207.32 metres.

(With PTI inputs)?