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Although flood hit the entire part of Chennai, Tamil nadu some three years ago, the quality of water is still found to be worse because of major inundation in these areas. The current inspection deals with the physico-chemical analysis of the ground water samples collected from ten locations in Neelangarai and Triplicane area in Chennai, Tamil Nadu and assessed using Heber Water Quality Index (HWQI) in the post tsunami circumstances. The factors examined were pH, fecal coliform, total dissolved solids (TDS), dissolved oxygen (DO), temperature biochemical oxygen demand (BOD) and turbidity. In addition to these parameters, pointers like electrical conductivity and salinity were also taken into consideration. The over all HWQI outcomes for all the trials in Neelangarai area were determined between 65.02 and 72.25 and Triplicane area was 66.64 - 70.71, which suggest that all the samples are medium to good in quality and could used for human consumption.

The continuous growth of population and increasing industrial activities in the different sectors, viz., textiles, leather, plastics, cosmetics and food processing industries require the development of varying nature of novel dyes. Among the dyes used in different industries, azo dyes are considered to be the most widely consumed and play an important role in the dyeing of textiles, leather, and plastics, etc. Azo dyes and their degradation products are toxic toward aquatic life and mutagenic for humans. The textile industry is one of the major contributors of azo dye pollutants and discharges the large quantity of azo dye effluents, which causes an acute hazardous effect on environment and human health. The conventional physical and chemical methods adopted to degrade azo dye effluents are not always efficient, due to the factors such as pH, temperature, and concentration of dyes. The existence of drawbacks on physico-chemical methods on the degradation of azo-dyes has triggered an interest for the researchers around the world to develop cost effective, alternative and eco-friendly techniques. Even though, the recent available reports indicate that the nanoparticles based microbial enzyme conjugates is considered to be an efficient technique to remove the azo dye from textile effluents within a few minutes, however, they are very high cost and possess difficulties in scale-up. In the present work, an attempt has been made to bring the relevant detailed literature available with regard to effective and efficient method and mechanism of degradation of azo-dyes in order to benefit the researchers of both from academia and industry. Furthermore, the present article also provides degradation based on their chemical structure and the conditions, in addition to mechanism involved for the bio-degradation and photo-catalytic degradation of azo dyes including merits and demerits of the each method.