Focus: GS III: Environment and Ecology
Why in News?
A recent report from the (CPCB) said that the number of polluted stretches in India’s rivers has fallen from 351 in 2018 to 311 in 2022 though the number of most polluted stretches is practically unchanged.
About the report
- The CPCB network monitors water quality at 4,484 locations in 28 States and seven Union Territories including rivers, lakes, creeks, drains and canals.
- The number of polluted river stretches categorised in ‘Priority 1 to 5.
- Priority 1:River stretches with a BOD exceeding 30 mg/L are considered the most polluted and thus need the most urgent remediation.
- Priority 2: Indicating a BOD of 20-30 mg/L.
- Priority 3: BOD between 10-20 mg/l
- Priority 4: BOD between 6-10 mg/l.
- Priority 5: Indicating 3-6 mg/L.
- While Gujarat and Uttar Pradesh had the maximum number of ‘Priority 1’ river stretches (6), Maharashtra had the maximum number of polluted river stretches i.e. 55, followed by Madhya Pradesh (19), Bihar (18), Kerala (18), Karnataka (17) and Uttar Pradesh (17).
BOD & COD
- The Biochemical Oxygen Demand or Biological Oxygen Demand, is a measurement of the amount of dissolved oxygen (DO) that is used by aerobic microorganisms when decomposing organic matter in water.
- The Chemical Oxygen Demand or COD is a measurement of the oxygen required to oxidize soluble and particulate organic matter in water.
Central Pollution Control Board (CPCB)
- The Central Pollution Control Board (CPCB) of India is a Statutory Organisation under the Ministry of Environment and Forests (MoEF).
- It was established in 1970s under the Water (Prevention and Control of pollution) Act.
- CPCB is the apex organisation in country in the field of pollution control.
- It is also entrusted with the powers and functions under the Air (Prevention and Control of Pollution) Act, 1981.
- It serves as a field formation and also provides technical services to the Ministry of Environment and Forests under the provisions of the Environment (Protection) Act, 1986.
- It Co-ordinates the activities of the State Pollution Control Boards by providing technical assistance and guidance and also resolves disputes among them.