Mumbai became the first metro city in the country where the price of petrol crossed Rs 100-a-litre mark after state-owned oil firms raised fuel rates for the 15th time this month.

Petrol price was increased by 26 paise per litre and diesel by 28 paise a litre, according to a price notification of state-owned fuel retailers.

The increase took petrol and diesel prices to a fresh all-time high across the country.

The price of petrol, which had already crossed Rs 100 in several cities in Rajasthan, Madhya Pradesh and Maharashtra, breached the psychological barrier in Mumbai on Saturday.

Petrol now costs Rs 100.19 a litre in Mumbai and diesel Rs 92.17 per litre. In Calcutta, petrol price rose to Rs 93.97 a litre and diesel to Rs 87.74.

Fuel prices differ from state to state, depending on the incidence of local taxes such as VAT and freight charges.

Rajasthan levies the highest value-added tax (VAT) on petrol in the country, followed by Madhya Pradesh and Maharashtra.

Oil firms had last raised prices on March 24, after which they started cutting prices till April 15 ahead of the Assembly elections in Bengal.

All rate revisions were stopped between April 15 and May 4, when they again raised rates. Therefore, there was a 41-day hiatus in rate hikes between March 25 and May 3.

Oil firms revise the rates of petrol and diesel daily based on the average price of the benchmark fuel in the global market in the preceding 15 days, and foreign exchange rates.

The price of petrol and diesel is the highest in Sri Ganganagar district of Rajasthan at Rs 104.94 per litre and Rs 97.79 a litre, respectively. After 15 price hikes this month, petrol has risen by Rs 3.54 per litre and diesel by Rs 4.16.

Oil industry sources said pump prices are also high because companies are recovering their past revenue losses when they pressed the pause button while global crude prices continued to spike.

International oil prices and rupee-dollar exchange rate impact domestic pump prices as India imports over 80 per cent of the crude oil it processes and pays in dollar.

The government deregulated the pricing of petrol in June 2010 and diesel in October 2014. Accordingly, state-run retailers are free to change pump prices every day. Since March last year, when the government raised excise duty on fuel to an all-time high, petrol price has increased by Rs 22.46 per litre and diesel by Rs 20.32.

The government levies Rs 32.90 per litre of excise duty on petrol and Rs 31.80 a litre on diesel.