The DGCA has now moved a plea seeking review and stay of the December 20, 2016 and the January 10 order of the tribunal claiming that it was impossible to dump human waste mid-air from aircraft toilet.
A bench headed by Justice Raghuvendra Singh Rathore issued notices to the original petitioner Lt Gen (Retd) Satwant Singh Dahiya and others while seeking their replies by May 23.
Mr Dahiya had moved the NGT alleging that faeces were splattered from aircraft on his South Delhi house before Diwali in 2016 after which the tribunal on December 20, 2016 had directed the DGCA to issue a circular to all airlines to pay Rs 50,000 as environmental compensation if their planes are found dumping waste mid air.
The petition has referred to the findings of the expert committee, constituted by NGT, and said there is no switch or system available in the aircraft to dispose waste in flight.
"The aircraft system has three level of in-built external protection for disposing the waste and under no circumstance release of waste during flight is possible and there has been no such resort ever by the operators.
"The modern day airline toilets are sealed and cannot be emptied in flight and toilet waste can only be disposed of by manual operation on ground during its servicing," the plea said.
The tribunal had earlier constituted committee comprising representatives from the DGCA, Central Avian Research Institute and CPCB to collect samples from the house of Dahiya.
The NGT had earlier directed the CPCB to take a clear stand whether it can differentiate between human excreta and bird poop.
Aviation regulator DGCA had maintained that it was impossible to dump human waste mid-air from aircraft toilet, and bird droppings had landed on the complainant's house, after which the green panel had ordered testing of the excreta samples.
The CPCB had said that there were traces of faecal coliform in the samples, indicating presence of human waste.
The tribunal had in 2016 held that if "any aircraft, airlines and the handling services of registered aircraft" were found to be dumping human waste from air or toilet tanks were found to have been emptied before landing, they shall be subjected to environmental compensation of Rs 50,000 per case of default.
The NGT had also asked the DGCA to carry out surprise inspection of aircraft landing at the airport to check that their toilet tanks are not empty while landing and prevent waste from being splashed over residential areas and any other place before landing.
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