MUMBAI: The Indian central bank has intervened in the non-deliverable forward, local over-the-counter (OTC) spot and the currency futures markets through the week to prevent the Indian rupee from slipping to an all-time low, four traders said on Friday.

Thrice this week, the rupee has been a mere one paisa away from its all-time low of 83.5750 per U.S. dollar, hit in April. It has held a narrow 10-paisa range this week, even though its Asian peers have witnessed choppy price action.

The currency was quoted at 83.54 at 1.30 pm IST on Friday.

A breach of the record low could spark volatility, which the Reserve Bank of India may be trying to avoid, the traders said.

"The rupee's intra-week volatility is way lower than the rest of Asia" largely because of the RBI's presence across markets, a senior treasury official at a private sector bank said.

The RBI did not immediately reply to an email seeking comment. The traders did not want to be identified as they are not allowed to speak to the media.

The central bank has regularly sold dollars in the OTC market this week, including on Friday.

It intervened in the non-deliverable forward (NDF) market just before the local market opened on Wednesday to ensure that the rupee did not fall below 83.5750 in the spot market.

Meanwhile, the total open interest on dollar/rupee currency futures has risen to over $4 billion, a 50% surge since May 31.

The RBI has "surely been selling June futures", a trader at a bank said.

The central bank's interventions have "undergone a change," Governor Shaktikanta Das said last Friday.

"We are now very clear and explicit that the RBI is there in the forward market," Das said.

The central bank has changed tactics in the way it seeks to limit rupee volatility, with the use of NDF preferred over spot market interventions, Reuters reported last month.

This has "been a pattern" with the RBI, to "cool off" NDF and "basically set up the trading session," a currency spot trader at a bank said. ($1 = 83.5130 Indian rupees) (Reporting by Nimesh Vora; Editing by Savio D'Souza)