Solve the curious case of colour-changing canines: What is turning Navi Mumbai dogs blue?

Stray dogs in Navi Mumbai could be turning blue as a result of untreated industrial waste being released into the Kasadi River. Stray dogs usually trudge into the river in search of food resulting in their fur getting dyed in a bright shade of blue due to the waste present in the river.

The Navi Mumbai Municipal Corporation tested the quality of water in the river and found that the treatment of waste was inadequate, Hindustan Times reported. The levels of biochemical oxygen demand (BOD) was 80 milligram a litre (mg/L) while the chloride levels were also found to be high.

BOD is the concentration of oxygen that is required to sustain aquatic life. Fish die if BOD levels are above 6 mg/L while levels above 3 mg/L make it unfit for human consumption, according to the guidelines of the Central Pollution Control Board. Chloride is toxic and harms vegetation, aquatic life and wildlife. The polluted river water can also affect human health.

The Taloja industrial area in Navi Mumbai has 977 pharmaceutical, food and engineering factories according to data obtained by NGO Watchdog Foundation through right to information (RTI). The untreated industrial waste being released into the river had raised its pollution levels up to 13 times the safe limit, HT reported.

"After numerous complaints to MPCB over the years, only the stench at Kasadi has reduced. However, the pollution levels continue to be extremely high and dissolved oxygen is negligible," Yogesh Pagade, a member of a local fishing community that conducted the study in 2016, said.

The Navi Mumbai Animal Protection Cell on Wednesday took photographs of a dog whose fur had turned blue. The group then filed a complaint with the Maharashtra Pollution Control Board (MPCB) the next day. In their complaint, the group said that the animals in the industrial area were suffering because untreated waste was being directly pumped out into the river.

"It was shocking to see how the dog's white fur had turned completely blue. We have spotted almost five such dogs here and have asked the pollution control board to act against such industries," Arati Chauhan, a resident of Navi Mumbai, who runs the animal protection cell, told the daily.

Chauhan added: "We have only spotted blue dogs so far. We do not know if birds, reptiles and other creatures are affected or if they have even died owing to the dye discharged into the air."

Taking cognisance of the complaint, MPCB Regional Officer, Navi Mumbai, Anil Mohekar, said: "Allowing the discharge of dye into any water body is illegal. We will take action against the polluters as they are destroying the environment. We have directed our sub-regional officer to investigate."

Officials from the MPCB surveyed the area on Friday and said that a private company has been using blue dye for several purposes. 

"The area is already cordoned off to the public and is in close proximity of the private company. However, five to six dogs entered the site looking for food and got the blue colour on them. We have warned the company owners to ensure no animals can enter again and such an incident should not be repeated," said Jayavant Hajare, sub-regional officer, MPCB Navi Mumbai.

Hajare added that the company has been told to remove the dye that is being pumped into the river within seven days. "If it is not removed then we will issue a notice," he said.

Waste from 347 small and medium-scale industries are treated at a Common Effluent Treatment Plant. The waste mostly consists of chemical, pharmaceutical and food processing waste. The industries in Taloja employ about 76,000 people with an annual turnover of Rs 60,000 crore.