Police in Indian Kashmir have warned residents to build underground bunkers to prepare for a possible nuclear war in the disputed region, which is on edge after a string of deadly border clashes.

The warning comes despite a ceasefire which took hold last week in the scenic Himalayan region, after the Indian and Pakistani armies agreed to halt cross-border firing that had threatened to unravel a fragile peace process.

India's Supreme Court on Tuesday postponed a ruling on whether the trial of five suspects for the fatal gang-rape of a student on a New Delhi bus should be moved out of the capital, officials said.

Defence lawyer M.L. Sharma filed a petition on behalf of his client Mukesh Singh seeking the transfer of the case to ensure a fair trial.

Five men went on trial Monday over the fatal gang-rape of student on a bus in Delhi as the victim's father urged the special fast-track court to deliver swift justice and sentence her attackers to hang.

With the case being held behind closed doors and subject to a gagging order, it was left to one of the prosecutors to announce the start of the case to reporters packed outside the sessions court in New Delhi.

India's Kumbh Mela, the world's biggest religious festival which sees up to 100 million people flock to take a bath in the river Ganges, is good for pilgrims' health, according to a new study.

Despite facing cold weather, endless noise, poor food and the risk of disease, Hindu devotees who attend such events report higher levels of mental and physical well-being, said the study by researchers in India and Britain.

The case against five adults accused of gang-raping and murdering a student in New Delhi was moved on Thursday for trial in a fast-track court, a lawyer for one of the defendants said.

"The magistrate has committed the case to the sessions court which is fast-track," Sadashiv Gupta, the lawyer for fruit-seller Pawan Kumar, told reporters outside a district court in south Delhi. The court would hold its first hearing on the case on January 21, Gupta added.

Aviation regulators on Thursday grounded most of the world's 787 Dreamliner fleet until a fire risk linked to the plane's batteries can been fixed, deepening a crisis for its U.S. manufacturer Boeing.

Regulators in Japan, India and Chile followed the lead of the U.S. Federal Aviation Administration (FAA) in ordering an indefinite halt to all operations, after a Japanese Dreamliner on Wednesday was forced into an emergency landing.

India's army has reached an "understanding" with Pakistan to "deescalate" military tensions in Kashmir after a recent deadly flare-up in the disputed border region, a spokesman told Agence France Presse Wednesday.

"An understanding has been arrived at between the two director-generals of military operations to deescalate the situation along the Line of Control," army spokesman Jagdeep Dahiya said in reference to a de facto border in Kashmir.

Pakistan has accused India of "warmongering" over deadly clashes in divided Kashmir, while calling for talks to end a flare-up that India has said spelled the end of "business as usual.”

Diplomats have warned against allowing a spate of cross-border killings to wreck a fragile peace process that had gradually warmed ties after a total break following the 2008 shooting and bomb attacks on Mumbai.

Pakistan's military said Wednesday that "unprovoked" firing by Indian troops had killed one of its soldiers across their tense border in disputed Kashmir.

The Pakistani army said in a statement that one of its soldiers had "embraced martyrdom due to unprovoked Indian firing" at the Line of Control (LoC).

India's prime minister said Tuesday there could be no "business as usual" with Pakistan after a deadly flare-up in Kashmir as New Delhi halted a new visa program and the fallout hit sports events.

While diplomats have warned against allowing four recent cross-border killings to wreck a fragile peace process, Prime Minister Manmohan Singh called the beheading of an Indian soldier on January 8 "unacceptable".