Gujarat Ambuja Cements Ltd, India's fourth largest cement maker, reported a 1.3 percent drop in quarterly profit on Friday as a result of sluggish prices in its key market.  The company, which has about a 14 per cent stake in rival Associated Cement Companies Ltd, said net profit in its fiscal second quarter ended December 31 was 595.4 million rupees compared with 603.2 million a year earlier.  Total income was 4.44 billion rupees.  A Reuters poll of 12 brokerages released on Wednesday estimated a 14 percent fall in net profit to 485 million rupees.  A drop in domestic cement prices in the past quarter was the sharpest in western India, Ambuja's biggest market, as Sanghi Industries Ltd's long-delayed 2.6Mta plant began production in Gujarat state, analysts said.