(a) 17 September
(b) 18 September
(c) 19 September
(d) None of these
The World Water Monitoring Day is observed globally on 18th September since 2003. This day is celebrated to increase public awareness and involvement in water monitoring and protecting water resources around the world. World Water Monitoring Day engages people of all ages in monitoring the condition of local rivers, streams, estuaries and other water bodies.