By James Lamont in New Delhi, Geoff Dyer in Beijing and William MacNamara in London Indian diamond cutters and polishers are lobbying the government in New Delhi to combat Chinese efforts to secure rough diamonds from Africa by providing the continent's nations with medicine and resources to build infrastructure. The Indian diamond industry leads the world in cutting and polishing the precious stones and says China is locking up the supply of rough diamonds by direct deals with African governments. The scramble for African diamonds reflects intensifying competition between the world's fastest-growing large economies for natural resources, particularly energy, minerals and land. China wants to develop a competitive cutting and polishing industry as domestic demand for diamonds expands. Indian executives see this as the biggest threat to their country's 60 per cent share of the world's diamond cutting and polishing. â€œThe Chinese government has been investing a huge amount of money to get hold of rough diamonds,â€ said Sanjay Kothari, a senior official at India's Gem and Jewellery Export Promotion Council. The council wants New Delhi to follow China's lead by exchanging rough diamonds for medicine and infrastructure project delivery and diamond cutting expertise with gem producers such as the Democratic Republic of Congo and Angola. It also wants the government to use India's foreign reserves to form a $4bn fund to support the sector. Vasant Mehta, the council's chairman, said some Indian companies had already done barter deals with African mining companies, exchanging diamonds for help to set up polishing factories. Beijing has signed multi-billion dollar resources-for-infrastructure deals with Angola, Congo and West African countries. These centre on oil in Angola and industrial metals in Congo, with less public attention to diamonds. The Indian allegations surprised some international diamond industry executives. â€œClearly southern Africa has been an important investment area for China â€“ but their focus has been on other areas, not rough diamonds,â€ said one.