The explosion occurred near a food cart close to Shahu toll plaza, a senior police officer said in Mumbai.
As per preliminary information, the bomb-like device was apparently placed inside a cardboard box near the food cart and when the vendor tried to open it, it blew up.
The injured, who is yet to be identified, suffered injuries in his hand, he said.
According to the officer, prima facie the explosion was that of a crude bomb.
An Anti-Terro Squad team is at the spot, sources said.