Conducted by: Directorate of Revenue Intelligence(DRI)

Purpose: To detect the hidden drugs in the gearboxes.

The drug syndicate used to remove the gears from old and used gearboxes and plastic packets containing the narcotic substance were placed in them and gearboxes were refitted to avoid detection.

These packets were then shipped concealing inside this metal scrap with other metal scraps so that it would go unnoticed by the authorities.

Source: ForumIAS blog