KOLKATA: Golpark in its southern part of Kolkata emerged noisiest locality in the country on the night of Diwali. On Diwali night, the noise level ranges between 54 dB in Delhi, Mandir Marg (Silence) to 81 dB Golpark in Kolkata. The Central Pollution Control Board 's (CPCB) study of noise level on Diwali night laid bare an uncomfortable fact about the city where the permissible noise level of fireworks is 90 dB as compared to 125 dB in rest of the country.The CPCB recorded noise level at seven cities on Diwali night. The maximum sound level observed at Golpark followed by Guindy and Perambur in Chennai. The minimum sound level observed at Mandir Marg (Silence) and Gachibowli (Silence) in Hyderabad.Trend analysis with respect to previous year data reveals that 56 locations have decreasing trend and 10 locations show increasing trend during day time. With respect to previous year data, it reveals that 53 locations have decreasing trend and 14 locations shows increasing trend during night time.No change observed at Sowcarpet (Residential) in Chennai, WBPCB HQ (Commercial) and RG Kar (Silence) in Kolkata and RSC Aliganj (Commercial) in Lucknow during day time whereas Whitefield (Industrial) in Bangalore, Taratala (Industrial) in Kolkata and Hazrat Ganj (Commercial) in Lucknow during night time."It is a myth that Kolkata has fewest violations of noise rules on Diwali night. This year, initial approval of chocolate bombs had encouraged traders to have a huge stockpile of bombs which were burst randomly," said ambient air quality expert SM Ghosh.India's apex pollution watchdog conducted real-time continuous ambient noise monitoring at 56 locations in seven cities with populations of over a million each, including Delhi, Mumbai, Navi Mumbai, Thane, Chennai, Kolkata, Lucknow, Bengaluru and Hyderabad.In March 2011, the central government set up the National Ambient Noise Monitoring Network (NANMN) through CPCB and the state pollution control boards (SPCBs) to monitor noise on a 24x7 basis in India's seven largest cities.Under NANMN, 70 monitoring stations have been set up in seven cities - each in Delhi, Bengaluru, Kolkata, Chennai, Hyderabad, Lucknow and Mumbai (including Navi Mumbai) - which are operated by state-level pollution control boards.The CPCB analysis asked state governments "to take measures for abatement of pollution emanating from various noise sources and ensure that the existing level do not exceed the ambient noise standards".The pollution watchdog also said that media, central and state governments, municipal bodies and pollution control boards should create awareness among students and public at large to avoid bursting of firecrackers.The most common source of noise pollution by far, the one that affects the most people, is motor vehicles.Aircraft and industrial machinery are also major sources, while office machines, sirens, power tools and other equipment are additional sources of noise pollution.The Noise Pollution (Regulation and Control) Rules, 2000, was last amended in January 2010 to reduce noise levels at night and from public address systems.