While no one has claimed responsibility, local authorities are pointing fingers at a separatist group.
Frustration with such strikes is rising in Pakistan. On Thursday, the parliament called for making talks with militants the 'top priority.'
Supporters of Proposition 8, which would outlaw the practice, nose ahead in polls.
The detention of Raj Thackeray, an anti-immigrant activist, threatens to stoke communal tensions against workers from northern states in India's financial hub.