Heavy rains hit normal life in Ahmedabad and Gandhinagar, while 10,000 people from rural and urban areas here were shifted to safer places after the Sabarmati river swelled.
Officials said the number of people who have lost their lives due to downpours in the state stood at 123 till yesterday.
In the last 24 hours, Ahmedabad alone received 200 mm of rainfall, according to official figures.
The Kalol tehsil in Gandhinagar received 370 mm of precipitation, including 240 mm between 8 am and 12 noon today, according to the data.
The district administration has ordered closure of schools and colleges. Many private offices and shops did not open up till late in the afternoon due to heavy rains.
Following the release of water from the Dharoi dam into the Sabarmati river, teams of the district administration and National Disaster Response Force (NDRF) shifted around 10,000 people, including nearly 2,500 from 11 locations within the city, during the morning hours, collector Avantika Singh said.
"The release of water from the Vasna barrage into the river has also caused inundation of low-lying areas," she said.
Portions of at least 20 buildings collapsed fue to heavy rains and water-logging. Three persons were injured when a building crumbled in Gaekwad Haveli locality in early hours today, Ahmedabad Chief Fire Officer M Dastoor said.
"Three persons were injured when a building collapsed in the city. Parts of nearly 20 buildings collapsed since midnight, while 64 trees have been uprooted. 11 instances of fire were reported due to short-circuits," he said.
"Our teams are also working in neighbouring Gamdi and Vanch villages to rescue the people stranded there due to water-logging," Dastoor said.
The Ahmedabad airport runway was partly flooded due to heavy rains, though it did not affect the air traffic, its director Manoj Gangal said.
Chief Minister Vijay Rupani toured the affected areas in a boat to take stock of the situation.
The Ahmedabad Municipal Corporation issued a warning to people not to venture near electricity poles and streetlights as it may prove fatal due to the water-logging.
Apart from Ahmedabad, Gandhinagar and Kheda also received heavy rainfall in the last 24 hours, affecting thousands of people who had to be relocated to safer areas.
Meanwhile, rescue and relief operations are on in Banaskantha and Patan districts which were flooded due to heavy rainfall and water released into the Banas and Sipu rivers from the Dantewada and Sipu dams a few days ago.
At least 29 people, including 14 of a family, died in the floods in Banaskantha district following torrential rains, officials earlier said.