Cyclone Fani has torn through India's eastern coast as a grade 5 storm, lashing beaches with rain and winds gusting up to 200km/h and affecting weather as far away as Mount Everest as it approached the former imperial capital of Kolkata.
The India Meteorological Department said the "extremely severe" cyclone in the Bay of Bengal hit the coastal state of Odisha, with weather impacted across the Asian subcontinent.
Dust storms were forecast in the desert state of Rajasthan, bordering Pakistan, heatwaves in the coastal state of Maharashtra on the Arabian Sea, heavy rain in north-eastern states bordering China and snowfall in the Himalayas.
Around 1.2 million people were evacuated from low-lying areas of Odisha and moved to nearly 4,000 shelters, according to India's National Disaster Response Force.
Indian officials put the navy, air force, army and coastguard on high alert. Odisha special relief commissioner Bishnupada Sethi said the evacuation effort was unprecedented in India.
By this afternoon, Fani had weakened to a "very severe" storm as it hovered over coastal Odisha and was forecast to move north-northeast towards the Indian state of West Bengal by Friday evening.
The airport in Kolkata, the capital of West Bengal, closed and at least 200 trains were cancelled across India.
The storm hit in the middle of India's six-week general election, with rain forecast in Kolkata forcing political parties to cancel campaign events.
The National Disaster Response Force dispatched 54 rescue and relief teams of doctors, engineers and deep-sea divers to flood-prone areas along the coast and as far afield as the Andaman and Nicobar Islands, which comprise a union territory about 840 miles east of mainland India in the Bay of Bengal.
Up to 4 inches of rain was expected in much of Sri Lanka, off the eastern tip of India.
More than 1,430 miles away on Mount Everest, some mountaineers and Sherpa guides were descending to lower camps as the weather worsened at higher elevations.
The government issued a warning that heavy snow was expected in the higher mountain areas with rain and storms lower down, and asked trekking agencies to take tourists to safety.
Hundreds of climbers, their guides, cooks and porters huddled at the Everest base camp, according to Pemba Sherpa of Xtreme Climbers Trek, who said weather and visibility was poor.
May is the best month to climb 29,035ft Everest when Nepal experiences a few windows of good weather to scale the peak.
On India's cyclone scale, Fani is the second-most severe, equivalent to a Category 3 hurricane.
Its timing is unusual, according to data from the Meteorological Department. Most extremely severe cyclones hit India's east coast in the post-monsoon season.
Because Fani spent 10 days gathering strength over the sea, it delivered a huge blow when it made landfall.
Some of the deadliest tropical cyclones on record have occurred in the Bay of Bengal. A 1999 super cyclone killed around 10,000 people and devastated large parts of Odisha.
Due to improved forecasts and better disaster management, the death toll from Cyclone Phailin, an equally intense storm that hit in 2013, was less than 50, according to the World Meteorological Organisation.