(Recasts with violence, adds politician bailed)
By Rina Chandran
MUMBAI Oct 22 (Reuters) - A 10-year-old boy was killed when police opened fire on protesters in eastern India on Wednesday, officials said, as rioters set trains alight and blocked roads in retaliation for attacks on migrants in the west of the country.
The child was hit by a stray bullet and died at the scene after police in Rohtas district, in the eastern state of Bihar, fired on a mob attacking a train station, Naval Kishore Mishra, a police officer, said from Rohtas.
At least six people and several policemen were injured when rioters threw stones and clashed with police, he said.
The migration of thousands of workers from impoverished northern and eastern states such as Uttar Pradesh and Bihar into India's booming financial capital Mumbai has sparked a violent backlash, with local resentment fuelled by ambitious politicians.
That in turn has provoked tit-for-tat violence in northern and eastern India, a sign of the strains that inequality is placing on society as parts of the country's economy booms.
On Wednesday, a local politician, whose arrest sparked violent protests in Mumbai was given bail after spending a night in jail.
Raj Thackeray, head of the small but vocal Maharashtra Navnirman Sena (MNS) party, was arrested on Tuesday for rioting and provoking attacks on migrants.
The party is known for its anti-migrant rhetoric and belief that Mumbai belongs to ethnic Marathis, who originate from the Maharashtra state of which the city is the capital.
"We had applied for anticipatory interim bail, which has been granted," a lawyer representing Thackeray told reporters outside the court in Kalyan town, near Mumbai.
A curfew was imposed to quell angry protests by MNS supporters. "He is now a free man. He can go home. His Diwali will start now," he said, referring to the Hindu festival next week.
On Wednesday in Mumbai, schools and shops were open and people returned to work.
But in Kalyan town, where Thackeray, the nephew of Hindu nationalist leader Bal Thackeray, was held, police beat back protesters with batons as Thackeray was brought to court.
Violence also flared in the poor north and east of India, where protesters set alight trains, blocked roads and damaged the home of the head of a Tata Motors factory, in retaliation for attacks on migrants by the MNS in Maharashtra.
In Bihar, gangs of young men torched coaches of a train, vandalised train stations and disrupted rail and road traffic. Several Bihar-bound trains were later cancelled.
"The situation is very tense ... we are facing a lot of trouble running the trains on time," a senior railway official in capital city Patna said.
In neighbouring Jharkhand state, a mob damaged the home of the head of a Tata Motors factory, also based in Mumbai, while in Uttar Pradesh, Chief Minister Mayawati demanded MNS be banned, echoing calls by other legislators in parliament.
Mayawati, chief of Bahujan Samaj Party, warned of a backlash against Maharashtrians in Uttar Pradesh and other states.
"There are many people from Maharashtra in other states who could be at the receiving end for none of their fault," she said.
Supporters of MNS, which is fuelling anti-immigrant rhetoric ahead of national and local elections due next year, had attacked north Indian railway job aspirants in Mumbai on Sunday, prompting calls for Thackeray's arrest and for the party to be banned.
MNS has previously also attacked migrant taxi drivers in Mumbai, a city where less than half its 17 million residents are from the state.
The Indian Express newspaper said it was not clear if Raj Thackeray would carry much weight in the elections.
"(But) with his arrest and its aftermath, he is certain to keep the spotlight and set the discourse." (Additional reporting by Sharat Pradhan in LUCKNOW; Editing by Bappa Majumdar and Alex Richardson)