Winds of up to 125mph and heavy rain slammed into India's east coast on Sunday, killing at least 21 people.
Cyclone Hudhud wrecked homes, uprooted trees, tore down power and communication lines, cut off road and rail links, and flooded thousands of acres of farmland in the states of Andhra Pradesh and Odisha.
Christian Aid's regional emergency manager, Dipankar Patnaik, said: "India's eastern coast and neighbouring Bangladesh are routinely hit by severe storms between April and November. This is the stark reality facing some of the poorest and most vulnerable communities.
"It is an incredibly worrying time. People fear for their safety, for their loved ones and for their livelihoods. Whole communities rely on farming and fishing to make ends meet. Rice, coconut, cashew and mango crops have been ruined, and with it people's source of income."
Christian Aid has started providing emergency supplies such as food and shelter but says it is hard to get to some areas because of the damage.