Air pollution levels dipped across Tamil Nadu on Diwali, the state pollution control board said Wednesday, a day after the festival was celebrated in the state for the first time after the Supreme Court order on the two hour window for bursting crackers came into force. Police have filed over 1,000 cases against those who burst firecrackers in violation of the two-hour time frame. The police crackdown, however, has drawn flak from opposition parties, which termed the action "ridiculous" and demanded withdrawal of all cases. A senior pollution control board official here said that data showed a drop in pollution levels across the state, including Chennai, on Tuesday. Citing data being collated from several parts of the state, he told PTI that there was a definitive drop in air and noise pollution levels on the day (when compared to previous years) and surveys showed that the parameters conformed to set standards in most regions. In Chennai, the Ambient Air Quality survey showed that pollution this year was much lesser and even almost conformed to the prescribed limits of 100\/micrograms as regards PM-10 (Particulate Matter). PM-10 ranged from 48 to 114 micrograms on Diwali day, compared to between 387 to 777 microgram the previous year, he said, adding gaseous pollutants (Sulphur di-oxide and oxides of nitrogen) were well within the prescribed standard of 80 micrograms. Ambient noise level ranged between 68 to 89 decibels on Diwali here compared to between 68 to 80 decibels last year, the official said adding the increase was "quite marginal" when commerical area categories are factored in. A senior police official here said cases were filed only against violators of the Supreme Court order, which had fixed a two hour time frame to bursting crackers. He said over 1,000 cases were filed across Tamil Nadu, including 340 in Chennai and 336 in Coimbatore and Tirupur districts. In Villpuram district, 160 cases were filed, while it was 105 in Tiruvallur, 79 in Kancheepuram 79, 50 in Vellore, 32 in Cuddalore and 31 in Tuticorin district. The cases were filed under Sections 188 (disobedience to order), 285 (negligent conduct with respect ot fire) and 286 (negligent conduct with respect to explosive substance) of the IPC against the violators, he told PTI. Another official said the number of police cases may be "2000 plus" since information was still being received from districts. Also, Diwali was celebrated Wednesday by natives of North India living in Tamil Nadu, he pointed out and added that cases would be registered if there were violations. Veteran CPI leader R Nallakannu and BJP Tamil Nadu unit President Tamilisai Soundararajan demanded that the cases be withdrawn. The Left leader said filing cases was not fair and added that there was no intention among those booked to violate the law. Both Tamilisai Soundararajan and Nallakannu said bursting of crackers should not be viewed as a "big criminal offence." CPI(M) State Secretary K Balakrishnan said filing cases "against children and their parents" was unnecessary. "Rather than acting on growing offences against women and girl children, it is ridiculous to book those who burst crackers and drag them to court or impose a fine," he told reporters. MDMK general secretary Vaiko said some children or youth might have burst crackers (that may have fallen outside the fixed time slot fixed) out of festival fervour. "They should be warned and filing cases against them is wrong," he said. On Tuesday several police stations in the state witnessed tense moments after violators entered into heated arguments with personnel. A 12-year-old boy died Tuesday while bursting firecrackers in Namakkal district. The state government had fixed the time for bursting crackers between 6 AM to 7 AM and 7 PM and 8 PM, confining the revelry to two hours in line with the apex court directive.