This is a khukuri, a curved Nepalese-style blade issued as standard equipment to members of the Gurkha, which are famed Nepali units of the Indian Army (and the British Army of India before Independence):
In 2010, a retired Indian Gurkha soldier, Bishnu Shrestha, was sitting on a train, when 40 dacoits (bandits) boarded the train and started robbing the passengers. When the robbers accosted an 18-year old girl and attempted to rape her in front of her parents, he acted:
The band of about 40 robbers, some of whom were travelling as passengers, stopped the train in the Chittaranjan jungles in West Bengal around midnight. Shrestha– who had boarded the train at Ranchi in Jharkhand, the place of his posting–was in seat no. 47 in coach AC3.
“They started snatching jewelry, cell phones, cash, laptops and other belongings from the passengers,” Shrestha recalled. The soldier had somehow remained a silent spectator amidst the melee, but not for long. He had had enough when the robbers stripped an 18-year-old girl sitting next to him and tried to rape her right in front of her parents. He then took out his khukuri and took on the robbers.
“The girl cried for help, saying ´You are a soldier, please save a sister´,” Shrestha recalled. “I prevented her from being raped, thinking of her as my own sister,” he added. He took one of the robbers under control and then started to attack the others. He said the rest of the robbers fled after he killed three of them with his khukuri and injured eight others.
I think the relevance of this to the spate of stories about rapes in India, especially on public transportation, is self-evident. The attitude that the victim is your sister is one that every man should have when seeing an assault like this.
At the very least, Indian trains and buses should have at least one Gurkha aboard, like we have flight marshals on planes!