Two gardeners were injured, one severely, when a banyan tree fell on them on the SSKM Hospital premises on Wednesday.

Shanti Bapari, 21, and Golam Kubat, 42, were tending to some plants in front of the administrative block when the tree came crashing down around 7.50am, an officer of the police outpost at SSKM said.

Bapari is being treated for head and spinal cord injuries at the hospital. Kubat was discharged after being treated for minor waist injuries.

"We were clearing debris left over by the rain when the tree crashed," Kubat said. "I was trapped under the leaves and small branches. Bapari was stuck under big branches. Some hospital employees pulled us out."

Bapari underwent a CT and an MRI scan. He will be operated upon, Karabi Baral, SSKM medical superintendent, said.

The tree, around 35ft high, stood in a garden maintained by the State Bank of India as part of its corporate social responsibility.

A bank official said the upkeep of the garden had been outsourced to a vendor, Pratibha Nursery.

Kubat, who lives in Birati, and Bapari, a resident of Madhyamgram, are contractual employees of the nursery.

Joydeb Chatterjee of Pratibha Nursery said the banyan tree, around 15 years old, had grown around another tree.

"That tree was in a rotten state and was made weaker by the incessant rain over the past few days," Chatterjee said. "The tree gave in and brought the banyan tree down with it."

Environment experts said the trees fell because of concreting of the area close to the base and unscientific pruning.

On Tuesday, a 60ft banyan tree fell near the Gariahat crossing, blocking both flanks of Rashbehari Avenue for close to six hours. The civic authorities plan to replant the tree in a smaller form at the same spot. "Once the tree is trimmed, we will try to replant it on Thursday," Debasish Kumar, mayor-in-council member (parks and gardens), said.

Five trees fell during the deluge on Monday. At least 120 trees in the Calcutta Municipal Corporation area had toppled on August 18 when a 70kmph storm hit the city. Four people died after uprooted trees fell on them.

Trinamul MLA and minister Aroop Biswas, who is the chairperson of the patients' welfare association of SSKM, met Bapari at the hospital.