Lafarge India Ltd is weighing the options of setting up greenfield units or taking over existing units in the country for growth.   The Indian subsidiary, which has presence in the eastern part of the country only by virtue of acquiring Tata Steel’s cement plant in Jamshedpur, would like to be a national player by establishing a strong market presence all over the country, chairman of Lafarge group, Paris, Bertrand Collomb said.   He said the company’s strategy for growth in developing countries like India was based on either setting up newer units or buying out existing ones. With an annual turnover of Rs 15 billion, the Indian subsidiary was contributing to two to three per cent of Lafarge’s worldwide revenues.   In the eastern region, the company had a market share of 25 per cent. It annual production capacity was 5Mt.