By Subir Bhaumik
BBC News, Calcutta
Attempts to cut pollution in the Indian city of Calcutta by banning old vehicles have failed after state lawyers did not appear in court.
Few vehicles in Calcutta are tested for pollution emissions
Judges dismissed the case as "invalid" after officials from West Bengal state's law department missed the crucial hearing.
The state government had earlier said it wanted to ban all vehicles made before 1990 in the fight against smog.
Air pollution in Calcutta is believed to be among the worst in the world.
In May 2005, the West Bengal government said that it wanted all buses, trucks and taxis manufactured before 1990 to be taken off the streets of Calcutta, because they were heavily polluting the city's air.
If the initiative had gone ahead, it would have meant that nearly 80% of the city's buses and trucks and nearly 50% of its taxis and auto-rickshaws would have been forced off the roads.
But the Bengal Bus Syndicate challenged the state government in the Calcutta High Court.
When the case came up for hearing on Wednesday before a division bench of the Calcutta High Court, nobody appeared for the government.
Justices Pratap Roy and Prasenjit Mondal had no option but to dismiss the case and declare the government notification invalid.
'Half-hearted and callous'
"The case has fallen through on technical grounds because there was no one to represent the government," said Swapan Dutta, a lawyer for the Bengal Bus Syndicate.
The office of the state's Advocate-General Balai Ray pleaded ignorance about the hearing.
"The transport department should inform us about the case date. Unless they do that, how can we send our lawyers?" an official in the advocate-general's office said.
The state government blamed the absence of a "junior lawyer" as the cause of the case falling through.
Environmentalist Subhas Dutta condemned the state government for not taking the issue of Calcutta's air pollution seriously enough. "They have been half-hearted and callous in pressing for the ban on old vehicles," he said.
The area around Calcutta is covered in smog
"This is a killer but the government is doing nothing to check it."
About 70% of people in Calcutta suffer from respiratory disorders caused by air pollution, a recent study by a prominent cancer institute in India concluded.
Ailments include lung cancer, breathing difficulties and asthma, the Chittaranjan National Cancer Institute (CNCI) study said.
One of its key findings was a direct link between air pollution among the 18 million people of Calcutta and the high incidence of lung cancer.
Calcutta tops all Indian cities when it comes to lung cancer - at 18.4 cases per 100,000 people - far ahead of Delhi at 13.34 cases per 100,000.