HIL (formerly Hyderabad Indu-?stries Ltd) has invested more than Rs 80 crore to venture in the manufacture of newer green building substitutes such as autoclaved aerated concrete blocks and polymer products. The $1.6 billion CK Birla Group company has launched advanced polymer products that can substitute the galvanised iron pipes used as plumbing pipes in buildings. ?Presently, our fibre cement roofing products account for 80 per cent of our revenue, while the green products make up the rest 20 per cent. We see this ratio becoming 60:40 in the next three to four years,?said Abhaya Shankar, Managing Director. The company has been trying to boost its turnover that had fallen to Rs 960 crore from Rs 1,160 crore in the previous year. ?But our last year?s capex was one of the highest. We expect this to yield results this year and hope to recover the fall in revenues. The first quarter performance is very encouraging,? he added.