Story highlights Police in Lucknow, northern India, have bought four drones to help control crowds

The unmanned aerial vehicles are being fitted with cameras and pepper spray to subdue angry protesters

Some Indians have questioned why police are resorting to "authoritarian and forceful methods"

(CNN) Police in India are putting aside their batons in favor of an overhead solution to angry and unruly crowds: pepper-spraying drones.

Yashasvi Yadav, Senior Superintendent of police in Lucknow, northern India, told CNN the city's force has bought four drones and is in the process of purchasing one more.

"The drones have been tested in controlled conditions," he said. "They have been very successful and will be used by the Lucknow police whenever there are violent protests or mob attacks."

The miniature aircraft will be fitted with a camera and pepper spray; each drone costs between $9,560 and $19,300, Yadav added.

Views on the new measure are mixed, with some concerned about the suppression of freedom of speech -- an already contentious issue in India. Last month, the country failed to enforce a law that would allow authorities to arrest people who post offensive material on social media.