Mumbai and neighbouring areas on Wednesday braced for cyclone Nisarga as it slammed the coast with wind speeds of up to 120kmph after tens of thousands of people in its path were evacuated, trains rescheduled, flights cancelled, fishermen ordered out of the seas and rescue workers put on standby.

Nisarga blew in from the Arabian Sea, making landfall at the coastal town Alibaug at around 12.30pm and the process will finish by 4pm, officials said. Already down on its knees from the raging Covid-19 pandemic, Mumabi will be hit by a cyclone for the first time in 72 years, Adam Soebel, a professor of atmospheric science at Columbia University in New York, tweeted.

Earlier, Soebel had said the last severe cyclone to hit Mumbai was 1891 but on Wednesday corrected to say the city was hit by a cyclone in 1948.

'It is likely to cross with an intensity of a severe cyclonic storm close to south of Alibaug,' India Meteorological Department (IMD) Mumbai's deputy director general of meteorology K.S. Hosalikar said.

'At that time, its speed is likely to be 100kmph to 110kmph, he added.

Steeped in colonial history, Alibaug is a quaint little town located about 110km from Mumbai, and is dotted with sandy beaches, unpolluted air and several forts and temples. A speedboat from Mumbai to Mandwa jetty near Alibaug takes 20 minutes and is an easy option for those wishing to avoid the arduous road journey. It is also home to many Bollywood stars and other rich people.

Nisarga, which is also expected to pummel the coastline of Gujarat besides Maharashtra, comes a week after cyclone Amphan wreaked havoc in West Bengal.

Hosalikar said Mumbai, Thane, Raigad and Palghar will be hit with winds of up to 100kmph to 110kmph. The IMD said the storm may also gust to 120 kmph. The winds will be accompanied by heavy to very heavy rainfall in the coastal districts of the state.

This Tuesday, June 2, 2020, satellite image released by Nasa shows cyclone Nisarga roaring toward the western coast of India. AP

The department has forecast the storm will have an impact on areas in North Maharashtra, Pune, Ahmednagar.

The department has said kuccha houses, trees, electric poles may fall as they may not be able to withstand the speed of the storm.

Pune-based Sucheta Nadkarny, 81, who lived in Mumbai suburb Vile Parle in 1948 said, 'I remember huge trees in our area were uprooted and plants in our garden destroyed. I was 10 years old then and remember this because my mother was heartbroken as the plants she had lovingly nurtured were destroyed,' Nadkarny told PTI.

The state government authorities have already asked people in vulnerable areas to shift to safer places.

Bracing for the impact of what is being billed as the most severe cyclone to hit Mumbai, the Central Railway (CR) rescheduled special trains and many airlines also cancelled their Mumbai operations.

The CR has rescheduled, diverted and regulated some trains on Wednesday, an official said. These include five special trains departing from Mumbai. Three special trains will be either diverted or regulated enroute, he added.

Maharashtra and Gujarat activated their disaster response mechanism, deploying NDRF teams and evacuating people from areas likely to be hit.

As a precautionary measure, the NDRF has evacuated around 1500 people staying in a shelter at Thal near Alibaug, an official said. The teams also evacuated people from Uttan and Mira Bhayandar, he added.

The teams conducted a reconnaissance of Palghar and Raigad coasts early on Wednesday, the official said.

Prime Minister Narendra Modi spoke to Maharashtra and Gujarat chief ministers on Tuesday and assured them all possible help from the Centre.

Nearly 43,000 people living near the coastline in Gujarat's Valsad and Navsari districts have been shifted to safer places as the state prepares to face the approaching cyclonic storm, officials said.

All fishing boats which were out in the sea off Palghar coast have returned, an official said.

As many as 577 fishing boats from Palghar had gone out in the sea and till Monday evening, 564 came back.

Later, help was sought from the Coast Guard, Navy and the fisheries department and the remaining 13 boats also returned to the shore late Tuesday evening, Palghar district disaster control chief Vivekanand Kadam said.

Ten teams of the National Disaster Response Force (NDRF) have been deployed in parts of Maharashtra for rescue operations in view of the cyclonic storm, chief minister Uddhav Thackeray said.

An alert has been issued for Mumbai city and suburbs, Thane, Palghar, Raigad, Ratnagiri and Sindhudurg districts.

Town planning authority MMRDA said nearly 150 patients at its COVID facility in Bandra Kurla Complex (BKC) in Mumbai were shifted as a precaution ahead of the cyclone.

The Navy has has kept five flood teams and three diving teams on stand-by in Mumbai, the official said.

These teams, trained and equipped for rescue operations, are stationed at various naval areas across Mumbai and can provide early response over a larger area, he said.

'We have evacuated more than 3,500 people from koliwadas (fishermen colonies) and temporary houses to safer structures like schools, community halls and government buildings,' superintendent of police Raigad, Anil Paraskar said.