Although there is a strict ban on the use of pressure horns, private buses operators ferrying passengers to different locations in the city continue flout the rule with impunity.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/despite-ban-drivers-pvt-buses-use-pressure-horns
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/tribune-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/punjab
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/noise-pollution
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/ludhiana-t
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/vehicular-pollution
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/environment