MUMBAI (Dow Jones)--Indian cement producers have raised prices in Mumbai by an average of 10 rupees ($1=INR45.57) per 50kg bag to INR165 per bag, due to growing demand from the housing and roads sector, industry officials said Friday.  "The demand is picking up fast. So we have gone ahead with a price increase of 10 rupees," said an executive at Grasim Industries Ltd., India's largest cement maker.  Demand for cement has been rising steadily in the past year after the government started work on a major road-building program.   An executive with Gujarat Ambuja Cements Ltd, India's fourth largest cement producer, said his company had also raised prices. "It has been different in different places. While in some, the prices are up by 5 rupees, in others there has been a raise of 10 rupees." This is the second time in a month that Indian cement producers have raised prices.