The National Green Tribunal, Southern Bench, has taken suo motu cognisance of a letter written to it by an octogenarian and decided to examine the need for a ban on high-decibel airhorns in the metropolis.

The Bench, comprising its judicial member Justice M. Chockalingam and expert member Prof. R. Nagendran, treated the letter as a petition and ordered notice to the Transport Commissioner and the City Police Commissioner.

In his letter, A.M. Joseph (80) of Luz Church Road said even after the Supreme Court banned the use of high-decibel air horns in the city limits for the past 18 months, all vehicles, including state transport corporations buses, were continuing to use them. He said the vehicle population was increasing alarmingly in the city.

He sought a direction to authorities to take action against use of banned horns by all vehicles in the city limits.