The Indian establishment sees it as an affront to one of its diplomats in New York, and thus to the country. The US administration insists it has played by the rules. The incident, which has now snowballed into a major diplomatic row, started with the arrest of Devyani Khobragade, India's deputy consul general in New York on Dec 12.

Khobragade was arrested on charges of visa fraud and underpaying her maid, Sangeeta Richard. Richard, an Indian national, started working for Khobragade about a year ago. On June 23 this year, she sought refuge with a US attorney. Indian officials claim to have informed the US of the development, and a day later New Delhi canceled Richard's passport, making her an illegal immigrant in the US.

In early July, Richard and Khobragade, along with other consulate officials, met at an attorney's office in New York, where Richard reportedly asked for $10,000 as compensation plus an ordinary Indian passport and a clean reference, which Khobragade is said to have refused.

Things got really messy from here, with Khobragade and her husband unsuccessfully trying to file a case in a New York court accusing Richard of extortion. In September, Delhi High Court passed an injunction barring Richard from filing any case against Khobragade outside India. A month later, Khobragade's family filed an official complaint with police, accusing Richard of extortion and naming her husband, Philip, as co-conspirator.

On Dec 10, two days before Khobragade was arrested, Philip and their two children flew to the US. That the US granted a visa to a person against whom a case is pending (which it rarely does) has prompted Indian officials to say that the Indian diplomat has been "trapped" in a "conspiracy".

The arrest of Khobragade has soured Indo-US relations to such an extent that even Secretary of State John Kerry couldn't assuage Indian feelings. Kerry called India's National Security Advisor Shivshankar Menon over the phone on Wednesday to express his "regret" over the "events that unfolded". In response, Indian Parliamentary Affairs Minister Kamal Nath said on Thursday that nothing less than an "apology" from the US for its "mistake" (of arresting, strip- and cavity-searching Khobragade and swabbing her for DNA) would satisfy India. "Just regretting and completing a formality is not acceptable ... The way they (the US) have handled this case, their behavior and attitude ... they will have to apologize," Nath said.