Sealdah is one of Asia's most congested railway stations and the small blast, which occurred during the rush hour, set off a stampede as thousands of people attempted to flee. Train services were disrupted for several hours. Calcutta is still reeling from an explosion on Tuesday in which more than 70 people died and 100 were injured when a device flattened a building used by gangsters as a brothel and gambling den.
Police experts are still searching for clues that might connect the two Calcutta bombings with last Friday's 11 blasts in Bombay, which left more than 275 people dead and 1,300 injured. Although the Bombay explosives were more sophisticated than the Calcutta bombs, police are investigating a tie-in between the Muslim underworld gangs in both cities.
In Bombay, police have arrested 11 men but their prime suspect, Yakub Memon, a hotel owner allegedly involved in drug- and gold-smuggling, escaped to Dubai. The United Arab Emirates government is considering an extradition request by India for Mr Memon and four other family members.
A chief investigator, M N Singh, claimed that the Memon residence in Bombay may have been the 'nerve-centre of the conspiracy'. The key to a motor-scooter loaded with plastic explosives was found during a raid on Mr Memon's flat. Police also captured two men who claimed they were paid 5,000 rupees ( pounds 106) by Mr Memon to park a car and a scooter laden with explosives in crowded shopping areas. Both bombs went off.
The Bombay chief investigator said police had nearly unravelled the bombing conspiracy. But as yet no plausible theory has been advanced as to why Bombay's criminal gangs would kill off so many people, unless they were paid to do so. But who hired them?
Some politicians accuse Pakistan of providing the cash and the expertise for the bombings. But no evidence has been released implicating Islamabad. Another possibility is that a radical Muslim group could have contracted the gang to get revenge on Hindus after Bombay's riots in December and January, in which most of the victms were Muslims.Reuse content