Dhemaji: An alert has been sounded in three Siang districts of Arunachal Pradesh and in Upper Assam after China informed India that the water level of the Tsangpo was rising.

The Tsangpo, as it is known in Tibet, flows as the Siang in Arunachal and the Brahmaputra in Assam.

The report from the Chinese government said the Tsangpo was swelling because of heavy rain in China. The various GD (gauge and discharge) stations on the Tsangpo had observed a discharge of 9,020 cumec water on Wednesday morning, reportedly the highest in 50 years.

The Central Water Commission, Dibrugarh, said people need not panic. The river had discharged 8,070 cumec water on August 14 and the difference of 950 cumec would not inflict severe damages, it said, adding that foolproof precautionary measures should be taken.

However, the administrations of the districts through which the Siang/Brahmaputra passes, have been put on alert. The Lakhimpur and Dibrugarh administrations in Upper Assam on Thursday cancelled leaves of all officials.

Dhemaji deputy commissioner R.A. Korati told The Telegraph on Thursday that they had held a meeting of the District Disaster Management Authority, sounded an alert and were prepared to tackle any situation. "We are monitoring the situation which is normal till now," she added.

A district flood bulletin said rise in the water level of the Brahmaputra because of heavy rain in the area over the past two days had inundated 26 villages, affecting 8,000 people, 356 livestock and several hectares of land, on Thursday.

In Arunachal Pradesh, the East Siang district administration asked people to be on alert and not venture into the river for fishing or swimming. The low-lying areas on both banks of the Siang, such as Jarku Paglek, SS Mission, Jorkong, Banskota, Berung, Sugar, Borguli, Seram, Kongkul, Namsing and Mer, were inundated in the morning. The administration was taking all precautionary measures for the safety of the people, sources said.

East Siang deputy commissioner Tamiyo Tatak said he was in contact with his counterparts in Upper Siang and Siang districts over the abrupt rise in the water level in the upper ridge since Wednesday night but it was not abnormal.

The swollen Siang has eroded its left bank in Mebo subdivision of East Siang district and engulfed eight houses in Seram village, said Manong Ratan, a member of Seram Anchal Samittee. He said the old Seram village (Ramku) had ceased to exist in 2000 because of massive erosion and flooding. The villagers were shifted to Palek, which too is endangered now. The Daying Ering wildlife sanctuary, on the bank of the river, is also inundated, threatening the fauna.

Tatak also reported to the state government that 30 people were stranded on an island of the Siang under Sille-Oyan circle of the district for the past 24 hours and needed to be air-evacuated. He said only the Indian Air Force could carry out the mission as the island does not space for a helicopter to land. He also informed the station air commander of Mohanbari air force station, Dibrugarh, of the situation.

Haren Pegu, a resident of Mechaki Sapori (sandbar) under Dhemaji said the Brahmaputra had swelled unusually on Thursday morning. "We were thinking that we had escaped the annual floods this year but things are looking grave now. We are, however, ready to face any circumstance," he added.

Mebo MLA Lambo Tayeng, adviser to Arunachal Pradesh chief minister Pema Khandu, is monitoring the situation.

Heavy rainfall has disrupted road communication in the Siang districts, a source said.