The most powerful cyclone to hit Bangladesh and eastern India in more than 20 years tore down homes, carried cars down flooded streets and claimed the lives of up to 20 people.

Authorities began surveying the damage Thursday after millions spent a sleepless night which saw 165km/h winds carrying away trees, electricity pylons, walls and roofs, and transformer stations exploding.

Authorities in both countries sent masks and sanitiser but social distancing was virtually impossible as families packed into reinforced schools, government buildings and community halls.

According to the India Meteorological Department, the cyclone is very likely to weaken into a deep depression during the next 3 hours.