Context: According to recent data from the Ministry of Environment and Forest (MoEF), the Sabarmati River, Gujarat is listed among the most polluted rivers in the country.

River Pollution in Gujarat

• Gujarat ranks fourth among the top five States with highly polluted rivers, with as many as 20 rivers in the critically polluted category.
• Main Reason: Lackadaisical approach of the authorities.

Consequences

• Dumping of waters with high COD (700 to 1000 mg per litre) into rivers.
• COD is a measurement of the oxygen-depletion capacity of a water sample contaminated with organic waste matter. It is used as a general indicator of water quality.
• If the COD is higher than 250 mg/litre, then it should not be released into the rivers.

Low Dissolved Oxygen (DO)

• It is the amount of oxygen that is present in water (i.e, the amount of oxygen available to living aquatic organism)

Sabarmati River
Origin and drainage

• It originates from the Aravalli Range of the Udaipur District of Rajasthan.
• It travels in a South-Westerly direction across Rajasthan and Gujarat.
• It meets the Gulf of Khambhat of Arabian Sea.

Basin

• Major part of the river flows through Gujarat as compared to Rajasthan.
• The basin is located in a semi-arid zone.
• The river traverses three geomorphic zones: rocky uplands, middle alluvial plains, and lower estuarine zone.
• It is a seasonal river whose flows are dominated by the monsoon, with little or no flows post-monsoon.
• Major Tributaries: Watrak, Wakal, Hathmati, Harnav, and Sei rivers.