With water storage in dams dropping to a “critical” level, the Centre has issued a “drought advisory” to Maharashtra, Gujarat, Karnataka, Andhra Pradesh, Telangana and Tamil Nadu, asking them to use water judiciously. The advisory was issued to Tamil Nadu on Friday and similar cautionary letters were sent to Maharashtra, Gujarat, Tamil Nadu, Karnataka, Andhra Pradesh and Telangana late last week, S.K. Haldar, a member of the Central Water Commission (CWC), said. The drought advisory is issued to States when the water level in reservoirs is 20% less than the average of live water storage figures of the past 10 years. Water falls under the State list and the advisory recommends States to use water for drinking purpose only till the dams are replenished. The CWC monitors water storage available in 91 major reservoirs across the country. According to the figures released on Thursday, the total water storage available was 35.99 billion cubic metres (BCM), which is 22% of total storage capacity of these reservoirs. The total storage capacity of these 91 reservoirs is 161.993 BCM. The figure was at 24% for the week ending on May 9. The situation seems to be grim in western and southern parts of the country. The western region includes Gujarat and Maharashtra. There are 27 reservoirs – 10 in Gujarat and 17 in Maharashtra – under CWC monitoring having a total live storage capacity of 31.26 BCM. The total live storage available in these reservoirs is 4.10 BCM until May 16, which is 13% of total live storage capacity. The storage in 27 reservoirs of these two States during the corresponding period of last year was 18% and average storage of last 10 years was 22%. The southern region includes States of Andhra Pradesh, Telangana, Karnataka, Kerala and Tamil Nadu. There are 31 reservoirs under CWC monitoring having total live storage capacity of 51.59 BCM. “The total live storage available in these reservoirs is 6.86 BCM, which is 13% of total live storage capacity of these reservoirs. The storage during corresponding period of last year was 13% and average storage of last ten years during corresponding period was 16%,” the CWC said.