Madras High Court on Thursday restrained oil companies from charging state-run transport corporations higher prices for diesel than the retail consumers till April 12.

Under the Union Govt.'s Ministry of Petroleum's new dual pricing policy for fuel, oil companies BP, HP and Indian Oil bulk consumers, such as transport bodies, are being charged considerably higher than retail users.

The Tamil Nadu government filed a petition with wanting the court to declare the huge hike of Rs 11.81 a litre in price of diesel to bulk consumers as unconstitutional. In the petition, the state government also claimed that most of its buses are making losses.

Justice S Rajeswaran of the Madras High Court granted the interim injunction till 12 of April, 2013.

Prior to the announcement of the Centre's dual pricing policy on January 18, the state's transport corporations were buying the fuel at a rate of Rs 49.72 a litre. But following the introduction of new system, diesel price jumped by Rs 11.81 a litre for bulk consumers, while just by 55 paise per litre for retail ones.

With the huge price, Tamil Nadu's state-owned transport corporations would incur an addition expense of Rs 743.55 crore per year.

Experts believe that Madras High Court's ruling could trigger a spate of similar petitions in other states across the country.