DR. A. S. ANAND, C.J.

These three tax revision petitions arising out of a common order passed by the Tamil Nadu Sales Tax Appellate Tribunal (Additional Bench), Coimbatore, dated 16th May, 1981, had been preferred by the Revenue and are being disposed of in common by this order. The assessment years in question are 1977-78 and 1978-79. A brief reference to the facts is necessary to appreciate the controversy raised before us.

The assessee is an association called Cement Research Institute of India. The objects of the association are to promote research and other scientific works connected with the cement trade or industry of trades and industries allied thereto, as also to maintain laboratories, workshops and conduct experiments. It is, an institution initiated by the cement industry and supported by the Council of Scientific and Industrial Research of the Government of India. The organisation comes under the overall administrative control of the Government of India and is financed in equal proportion by the Government of India and its members. The assessee purchased raw materials like limestones, gypsum, literate, sand, etc., for their day-to-day research activities. The