Delhi Mayor Arti Mehra has assured Health Minister Yoganand Shastri of "full cooperation' in preventing and controlling water and vector-borne diseases. Ms. Mehra said on Wednesday that though there had been a noticeable decline in such diseases, a lot was still required to be done. "The Delhi Government and the civic body need to complement each other and work together towards preventing these diseases. Pipes need to be replaced in time so that no mixing of sewage water and drinking water takes place. It is therefore imperative that necessary steps are taken jointly by all authorities concerned to replace these pipes where required,' she added. "Several water tanks in the city are functioning without the mandatory chlorinators leading to inadequate infusion of chlorine in the water supply. Many water supply tanks too have not been cleaned on time and regular cleaning is rarely undertaken,' she added. Ms. Mehra directed the officials concerned to look into the matter and said the civic body was also striving to complete the cleaning work of drains on time. "Necessary directions to accelerate these works have already been issued and I am closely monitoring the progress,' she added.