Dhruvkumar Lallubhai Desai, whose complaint threatened to blow a Rs 6,300-crore hole in the books of 11 cement producers. The cement producers may have the name of a grouping of 13,000 construction contractors and realty firms. But it is the work of the 74-year-old, who has been waging a crusade against cement makers. Single-handedly. For six years, and counting.It was Dhruvkumar Lallubhai Desai, a trustee of the Builders’ Association of India, who compiled and submitted a 3,500-page application to the country’s competition regulator in July 2010 that alleged cement producers were colluding to fix prices. On June 20, the Competition Commission of India held 11 cement companies guilty of operating like a cartel, and the industry’s apex association of abetting them.For Desai, it was a victory against many odds. The complaint to the CCI was made despite a previous complaint to another government regulator pending for four years and despite the very people he represented having ceased to believe.A CCI ruling favourable to the BAI has infused new energy in the fight of the 81-year-old association-whose members include L&T, HCC, Simplex Infra, DLF and Hiranandani Group-against cement producers.For the past six years, Desai has spent much of his working hours on this case, compiling documents, crunching numbers, tracing patterns and studying regulation. Heaps of paper and files on cement prices, dispatches and production, among other things, crowd his desk in the small BAI office on the seventh floor of a highrise in Tardeo, south Mumbai.