 In 1977 the Kerala Forest Research Institute carried out an ecological impact study of the Silent Valley area and proposed that the area be declared a biosphere reserve.In 1978 Indira Gandhi, Prime Minister of India, approved the project, with the condition that the state government enact legislation ensuring the necessary safeguards.Also that year the IUCN (International Union of conservation of nature) passed a resolution recommending protection of lion-tailed macaques in Silent Valley and Kalakkad and the controversy heated up.