One firefighter died after a mound of excavated soil fell on him and three others in Dapodi area of neighbouring Pimpri Chinchwad township on Sunday evening, police said.
A labourer also got trapped under the soil and efforts are on to rescue him, they said.
According to police, around 20-feet deep trench was dug for drainage while the soil was piled up at the ground level.
"One labourer accidentally fell into the trench while working and started calling for help. Two local residents immediately went down and tried to rescue him. Soon, the fire brigade personnel arrived at the spot," a senior police officer with Pimpri Chinchwad Police said.
"Three firefighters entered the trench and rescued the two local residents and sent them to safety above. But while they were trying to rescue the labourer, a mound of soil fell on them and all four got trapped," he said.
Other fire brigade personnel rescued their trapped colleagues. One of them was in a critical condition and later died, the officer added.
"The labourer is still trapped down under and efforts to rescue him are on. An NDRF team is also a part of the operation," he said.