According to a police officer, the incident took place at 10.48 am near the Bandra railway terminus.
"After the pipeline burst, huge quantum of water got accumulated in the area, where the two children drowned," the police officer said.
According to a civic official, the children were playing around the pipeline when the incident occurred.
The deceased were identified as eight-month-old Vighnesh Doiphode and his nine-year-old sister Priyanka, he said.
"While Vighnesh was rushed to Bhabha Hospital, Priyanka was taken to V N Desai Hospital. However, both of them were declared dead," the Brihanmumbai Municipal Corporation (BMC) official said.
More From This Section
BMC officials said they are trying to know what exactly led to the pipeline rupture.
"We are trying to find out the reason behind the pipeline burst. We have immediately stopped the water supply and pipeline repair and maintenance work is on...It seems that the decades-old pipeline could not bear the excessive pressure of water, which led to the incident," the official said.
In 2009, the Bombay High Court had directed the BMC to remove the slums located along the main water pipelines in the city and demarcate a ten-metre buffer zone.