Severe flooding in India’s tea-growing state of Assam and neighbouring Nepal has killed at least 200 people and displaced millions, severely hampering efforts to stop the spread of coronavirus.

In Assam, heavy monsoon rains burst the banks of the Brahmaputra River, causing more than 2,000 villages to be enveloped in floods and mudslides and displacing 2.75 million people in the past two weeks. There have been 85 deaths reported in the state.

Keshab Mahanta, Assam’s water resources minister, said: “The flood situation remains critical with most of the rivers flowing menacingly above the danger mark.”

Officials voiced concern that the flooding and hurried evacuation of millions of Assam residents would cause a significant rise in cases of coronavirus in the north-eastern state, known for its tea plantations. At the moment, 50,000 people are sheltered in cramped relief camps but because of the scale and urgency of the evacuations, officials admitted that no physical distancing measures were being enforced.

Sanghamitra Sanyal, a member of Assam’s flood management force, told Reuters: “It’s hard to enforce social distancing when people are being ordered to move away from the rising waters.

“We’re urging people to at least cover their mouth and nose with a piece of clean cloth.”

The number of Covid-19 cases is still increasing rapidly in Assam, with more than 1,000 new infections reported daily, pushing the state’s total to almost 25,000 cases. Last week the total cases in India surpassed a million, making it the third worst affected country in the world.

Officials from the Assam State Disaster Management Authority (ASDMA) urged authorities to deal with complaints that mismanaged and contaminated coronavirus waste, including used masks and other personal protective equipment, was washing up in the floodwaters in areas of Guwahati, the largest city in Assam.

Authorities confirmed that hundreds of animals had drowned in the flooding, including nine endangered rhinos living in Kaziranga national park, a Unesco world heritage site.

Kaziranga national park and tiger reserve, which is home to 2,400 of the one-horned rhinos – the largest concentration of them in the world – has been severely affected by the flooding, with 85% of the 407 sq mile (1,055 sq km) park underwater. Officials said that 59 of the 223 anti-poaching camps had been inundated and as well as the rhinos, among the dead animals were deer, porcupines and Asiatic water buffalo.

Flooding and mudslides are an annual occurrence in Assam, but because of global heating their frequency and intensity are increasing. This year’s monsoon rains have affected 28 of the state’s 33 districts – some of the worst flooding in years. Successive governments have made promises to strengthen the state’s flood defences but projects have remained mired in corruption and inefficiency.

Nepal also bore the brunt of the floods, with 110 people killed and 50 still missing in the rising waters and mudslides, while more than a million people were displaced. With heavy rains expected to continue over the next few days, authorities said the number of dead was likely to increase.