MUMBAI: In a city which rarely stops to help someone in distress, Aadesh Gajre a youngster from Badlapur, has performed a task as rare as his blood group — the Bombay Rh-negative .

He braved the heavy rains on Sunday and the crippling mega block on the Central Railway to reach a blood bank in Bandra around 8.30 pm to donate blood for a seriously ill patient in far-off Kochi.

Blood banks generally don’t accept donations on Sunday evening, but doctors at Mahatma Gandhi Seva Mandir Blood Bank made an exception given the 21-year-old Aadesh’s humanitarian gesture. “I don’t know who he is, but had to do it because no one else in India could have helped him at that moment,’’ Aadesh told the TOI.

Indeed, the Bombay blood group is among the rarest blood groups. The rarity of Adesh’s blood group can be gauged by the fact that there are only about 70 eligible donors across the country. Think Foundation, an NGO that helps patients and families with organising blood, has a list of 25 people in the city with the Bombay positive group and only four with the Bombay negative group.

“Social networking sites and newspapers in Kochi had carried a plea for donors of this rare blood, but couldn’t come up with any donation,’’ said Think Foundation’s Vinay Shetty. “When ever we get a request for this blood group it’s a nightmare call,” Shetty added.

Renjeeve V R, a 26-year-old at Medical Trust Hospital in Kochi, had undergone a bowel resection and needed blood transfusion urgently to recover. “We learnt that the few eligible donors in Bangalore couldn’t be contacted. So we began contacting people on our list,’’ said Shetty. Two numbers were untraceable and the third was out of town.

That left them with Aadesh, who until Saturday didn’t know that he had such a rare blood group. “I have been donating blood at Bharat College where I study for the last two years, but I wasn’t ever told that I had the Bombay blood group,’’ said Aadesh. On learning that he was the only help available for Renjeeve, he carried out the Badlapur-to-Bandra trek on Sunday determined to help a person he doesn’t even know.

As for Renjeeve, the blood components reached him by air on Tuesday. ``The operation was successful, but he will need two three more bottles,’’ said his college friend, Bangalore-based Sharat Parabhakaran who is coordinating the effort.