Dhaka, April 26 -- A massive blackout has disrupted power supply to 21 districts in southern Bangladesh after a national grid line tripped on Saturday afternoon.

The outage began around 5:48pm, plunging districts across the Khulna and Barishal divisions into darkness, according to authorities.

Mohammad Haider Ali, managing director of the West Zone Power Distribution Company Limited (WZPDCL), said the blackout was triggered by a problem at Gopalganj's Amin Bazar, a key transmission centre for electricity generated from the Rampal and Payra thermal power plants.

"The issue is believed to have been caused by a sudden increase in load due to the heat," he said. "However, the situation is gradually improving, and electricity is being resto...