NEW DELHI: Honking of vehicles is a bigger noise polluter than firecrackers with decibel levels going up to 100. In comparison, crackers emit up to 90 decibels noise.This was revealed by a study conducted in February and March for around 30 days by Indraprastha Institute of Information Technology (IIIT), Delhi. It was found that honking noise, especially from two-wheelers, is far more problematic as it continuously occurs for hours daily.The researchers measured noise pollution on eight prominent roads and 12 intersections of the city. They found that roads with a metro line or station are far noisier as concrete reflects sound.Pravesh Biyani, assistant professor with Electronic and Communication (ECE) department of IIIT, which conducted the study, said that they used a customised instrument to measure the noise for 60 continuous hours over several days.“We removed the honking noise from other noises that you generally hear on the roads. Since I work on speech source separation field, we used that to identify honking from a mixture of sounds. It was found that on a given day, the decibel levels of honking reached up to 100 decibels. Two-wheelers are the biggest culprits for noise pollution because their numbers are higher than cars,” Biyani said.The research stated that if honking is reduced in vehicles, it could help reduce noise pollution by a huge amount. “However, we need to take other steps, especially on roads that have an overhead metro station or line. At Govindpuri station, we found the decibel level reaching 100,” said Biyani.“There is a need to put noise absorbers on metro pillars and stations as well as road dividers. We found that concrete is not a good noise absorber and, in fact, reflects sound. Because of this, the decibel levels were a little higher on roads with a metro station,” Biyani said, adding that IIIT will release their research data with decibel data sets and videos of roads soon. “We want to put our results in public to assist other researchers,” he said.Continuous noise can be damaging to the ear. “Hair cells in the ear get damaged severely if one is exposed to loud noises for a long period,” said Dr Ravi Meher, professor at Maulana Azad Medical College. “The damage depends on the intensity of the sound. If the noise is in the range of 80-90 decibels, then it can damage ears within eight hours. If the sound increases to 100 decibels, then one can get affected in less than six hours,” he added.A team of student researchers at IIT-Delhi had showcased a study done by them during Industry Day on September 21. “Natural products like jute, husk and cotton can be effective noise absorbers,” said a research poster on display.