The Karnataka State PollutionControl Board has started the study of polluted river stetches and lakes in Karnataka, an official said."We have given a direction during the COVID-19 related lockdown to assess the water quality. We have asked our Research Scientists, chief environment officers and environment officers of all the districts including Bengaluru to furnish lab analysis report before the lockdown is over," KSPCB member secretary Basavaraj Patil told P T I.The KSPCB has identified 17 river stretches as polluted and want to study them."We have 17 polluted river stretches, which are Tungabhadra, Cauvery, Kabini (Kapila), Krishna, Bhadra, Ghataprabha, Malaprabha, Arkavati, Shimsa, Bhima, Hemavati, Lakshman Teertha, Kaali, Netravati, Manjira, Kumaradhara and Kagina," the officer added.According to Patil, the water quality has improved in the rivers flowing in the state.However, the KSPCB wanted to analyse the extent of improvement of water quality.The officers in all the districts have been asked to collect water sample of all the rivers and furnish the report before the lockdown is lifted.In Bengaluru, the officers will collect water sample in three lakes such as Bellandur, Agara and Varthur using Personal Protective Equipment.The water bodies in Bengaluru are highly contaminated.Bellandur lake, the biggest water body in Bengaluru is so polluted that it had caught fire due to chemical reaction drawing national attention.In its latest study on the lockdown effect on air quality, the KSPCB found that the pollution level has come down by 65 to 70 per cent.