Navy blue has traditionally been associated with the military because it's an official naval shade of the United States' armed forces- the Navy and Marine Corps. Every service member must be properly dressed in navy blue when off duty or attending official functions such as mess dinners or parades. For this reason, many military personnel associate navy blue with military decorum and discipline. They also feel that wearing navy blue makes them look smart and courageous in front of their colleagues. Consequently, soldiers often wear their best navy blue when off duty to boost their self-confidence and morale.
However, there are some who believe that girls look sloppier and less refined when they wear navy blue. The belief is that girls become more susceptible to chikan when they wear blue clothes- especially blue blouses. Essentially, boys find it easier to target female commuters when they're wearing blue blouses. This has led many parents to encourage girls not to wear blue when out of the house. Some have even barred their daughters from wearing certain colors when on the road.
Navy blue is a classic color that's frequently used in clothing. It's also a masculine hue and is often associated to the military. Chikan - the act of harassing someone with sexual intent - is often associated with blue. Many chikan incidents occur at train stations in which men harass female commuters in navy blue blouses. Some have suggested that wearing navy blue makes a person more susceptible to chikan. Essentially, ladies should avoid wearing navy blue when out and about.