The ancient people of India divided the day and night into sixty parts, each of which was called a 'ghari' [a ghari = 24 mins]. The night and day were each divided into 4 parts, each of which were called a 'pahar'. For time keeping purposes in each town Indians employ a group of men called 'gahriyallis'. These group of men hung a round brass tray two fingers thick called a 'ghariyal' at a high place specially constructed for this purpose. On the ground they place a vessel filled with water and immersed in it another vessel with a hole. Every time this vessels fills up once every ghari [24 mins] the ghariyallis would strike the brass tray with a mallet. For example, when the vessel that they put in the water at daybreak fills up once, they strike the ghariyal once. When it fills up twice they strike it twice and so on until a pahar is completed. The close of each pahar is announced by striking the ghariyal many times in rapid successions pausing and striking the pahar for example twice if it is the second pahar or thrice if it is the third pahar, so on and so forth for the fourth, fifth, sixth etc. When the four pahars of the day are over the night pahars were also introduced in the same way.
Note: This kind of time keeping has been followed all over India for many centuries since the invention of time keeping and this may have been the predecessor of town clocks across the western world.