India's political discord and the lack of one empire made it a ripe target for invasion.
Explanation:
India was one of the richest nations of the world but there was discord in the populace with smaller states vying for power and no singular empire.
The degradation of the nobility allowed the British to use their discord against them and take over the country.
India was affected heavily by colonialism as it by effect, changed the geography of the country and was responsible for a huge economic drain which left the country poor and hapless.