India Jihad Update: "India: Bomb Blasts in Mumbai," from [1] Stratfor:

Three to six bombs exploded on commuter trains in Mumbai, India, during the evening commute July 11. Blasts were reported along the Western Rail Line at the Khar, Matunga, Mahin, Jogeshwari and Mira Road rail stations. All local trains in Mumbai have stopped.

The perpetrators of this attack are likely members of Islamist militant group Lashkar-e-Taiba (LeT). Indian security forces have uncovered a number of LeT cells in and around New Delhi and Mumbai in recent weeks. The cells had plans for coordinated attacks against infrastructural targets, including ports and rail lines. Prior to the blast, a number of bomb threats were made against major Indian rail lines. These actions in the lead-up to the Mumbai attack are consistent with the militant tactic of "pinging the system" to detect response times and give victims "threat fatigue."

India was due for a militant attack by LeT in a major urban area. Though Indian security forces have been particularly effective in uncovering a number of LeT cells throughout the country, they failed to completely disrupt LeT's plans.