This was because the cost of importing refined products had fallen.
Since 2010, every month the east African nation has set a cap on prices of petrol, diesel and kerosene, to protect consumers from unfairly high prices.
But the system has angered consumers in recent months as local prices have failed to reflect the slump in the price of crude oil in global markets.
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The ERC reduced the maximum price of a litre of petrol in the capital Nairobi by 4.5 per cent to 102.01 shillings ($1), but still far higher than the 70-80 shillings it retailed at in 2009, when the price of crude was at around the current levels.
The commission also reduced the price of a litre of diesel by 3.67 shillings to 90.85 shillings and that of kerosene by 4.94 shillings to 71.37 shillings.
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Joseph Ng'ang'a, the director general of the ERC, said the weakening of the Kenyan shilling against the dollar had curbed the commission's ability to cut prices more.