Context: A troop of Gray or Hanuman langurs with their fur/hair coloured blue, due to exposure to chemical-based dyes, was spotted in an industrial neighbourhood of Ankleshwar in Gujarat recently.

What is the reason for their blue-colored fur/hair?

• The town of Ankleshwar is well-known for its industrial units manufacturing dyes and intermediates. The industrial activity in and around Ankleshwar has led to much of its environment, including its air and water sources, being polluted.
• Norms set by the Gujarat Pollution Control Board, Central Pollution Control Board as well as the Directorate of Industrial Safety and Health are usually not followed.

What is the impact?

• Many of the chemicals used in the industrial units are carcinogenic and have been reported to cause skin ailments as well as cancers among workers.

About Gray or Hanuman Langur (Semnopithecus entellus)

• Distribution: They are found across South Asia. Its 16 subspecies’ range extends from the Himalayas in the north to peninsular India in the south.The bulk of the gray langur distribution is within India. In the Indian Subcontinent, their distribution is reported in Bhutan, northern India and Nepal.
• Presence in India: Hanuman Langurs are found in almost all the parts of India. They are easily spotted in the Bandhavgarh National Park and Sariska Tiger Reserve.
• Habitat: It is found both in forests and near human habitations. They prefer tropical, dry thorn shrub, pine and alpine forests as well as urban areas.

Conservation status

• IUCN red list = LC (Least Concern)
• CITES = Appendix -I
• Wildlife Protection Act, 1972 = Schedule I