The Azhadirachtin in Indian society has been considered higher than kalpavriksha, the mythological and ethanobotanical beneficial properties. The efficacy of neem as a medicine has been documented in several different ancient treatments like the Atharvana Veda, the Ghrhyasutra and Sutragrantha and in puranas. The acidic principles in neem as margosic acid with three acetive constituents, viz., nimbin, nimbidin and nimbinene. Chemically related and biogenetically derivable from a tetracyclicterpene are the key features of them. These chemicals, for example, pesticides, antifeedants and cytotoxic properties, also show a whole range of biological activity.

Climate change is one of the most serious threats for sustainable agriculture development, with adverse impacts expected on the environment, human health, food security, economic activity, natural resource's management, and physical infrastructure. The aim of the study is to identify the impact of climate change on the farmers and adaptation measures. The study is carried out in the Namakkal district of Tamil Nadu which is a semi-arid region. Data is collected by primary field survey and Participatory Rural Appraisal (PRA) methods. The rainfall and temperature data for the past three decades is analysed to assess the seasonal and annual rainfall pattern. The statistical methods such as correlation and regression were used to analyse and assess the impact of climate change on the farming community. A sum of 500 small and marginal farmers were selected randomly from different panchayats in districts to collect the data. According to farmers, this problem is linked with the reduction in the number of rainy days for all seasons. It is identified there is a decreasing trend in the rainfall for the past eight years and temperature is increasing at a faster rate. The climate variability and the trends observed in the study area has direct and indirect impacts on the farming community in the region, effective adaptation measures are suggested to address the impacts of climate change.