Downpours have killed at least 200 people and submerged homes and farms in Tanzania, Kenya and Burundi.

At least 200 people were killed and dozens more were injured across East Africa in recent days, officials and aid groups said, as torrential rains, floods and landslides pummeled towns and cities in a region already grappling with the devastating effects of the climate change crisis and dilapidated infrastructure in poor areas.

The extreme rains unleashed a wave of destruction across Tanzania, Kenya and Burundi, flooding homes, demolishing businesses and leaving many people stranded on rooftops.

The downpours exposed yet again the bad roads and poor drainage systems in some of the region’s biggest cities, which residents have persistently complained about. They also revealed how poor people, who live in sprawling shantytowns without access to proper roads, water or power, bear the biggest brunt of destructive floods.

On Thursday, activists and opposition figures across the region called on governments to do more than respond to the extensive destruction wrought by floods, by improving infrastructure to lessen or prevent such flooding in the first place.

Raila Odinga, a longtime opposition figure in Kenya, said authorities should learn from the ongoing devastation and take long-term measures to save lives.

“Preparedness is key to forestalling a crisis of larger proportions,” Mr. Odinga said in a news conference. “We can do better than crying for help when the rains come and crying for help again when the rains fail.”

In Tanzania, at least 155 people were killed and 236 others were injured by the relentless rain that has swept several parts of the country in recent days, Prime Minister Kassim Majaliwa said on Thursday.

Speaking during a session in Parliament, Mr. Majaliwa said the rains had affected some 200,000 people and heavily damaged farms, bridges, roads, schools and places of worship. About 10,000 homes in Tanzania were also damaged to varying degrees, he said.

The heavy downpours this week affected informal settlements in the Temeke and Ilala districts, which are part of the commercial port city of Dar es Salaam. Some roads were also submerged and temporarily closed on Tuesday in Dar’s Jangwani, Mkwajuni and Kigogo neighborhoods, all of which are prone to floods. Parts of Morogoro Road, which leads into the central part of the city, were also underwater, leading to the suspension of the rapid-bus network.