Complex sentence: It costs Rs.1800 ($45 ~), which is about one fourth the price of existing water purifiers in the Indian market which are largely based on ultraviolet technology and require both electricity and pressurised tap water to function.
Split into simpler sentences: It costs Rs.1800 ($45 ~), which is about one fourth the price of most existing water purifiers in the Indian market. Existing purifiers are mostly based on ultraviolet technology and require both electricity and pressurised tap water to function.