Airlines denied the practice of Blue ice:
Domestic airlines have denied dumping human excreta mid-air. They said the lavatory waste is stored in a tank inside the aircraft. It is cleaned by the ground crew only after the plane lands.
Dumping of waste during the flight may happen rarely due to leakage. Some aviation experts said it was not possible for a pilot to dump a tank while in flight, as there were no controls inside the aircraft for doing this.

What is blue Ice?
Blue ice, a term used for frozen sewage material leaked mid-air, as a “rare occurrence” which signifies “a leaking toilet system, leading to the formation of ice in high altitude.”

National Green Tribunal (NGT) ordered a fine of Rs. 50,000 on airlines emptying toilet tanks in the air.
In its order, the NGT had asked the Directorate General of Civil Aviation (DGCA) to issue a circular to all airlines using the Delhi airport to ensure that they do not release any waste while landing or taking off at the airport or near it.

Petition filed:
The petitioner had told the court that excreta fall on houses near the airport due to “evacuation of the aircraft toilet canisters while flying.