Has population of 494,070,000 (3rd4)
Size: 4,324,782 km² (7th4)
Languages: Same as number of countries
Consists of 28 States
Population: 1,126,000,000 (2nd)
Size : 3,287,263 km² (7th)
Official languages : Hindi, English and 21 other
Based on the statistics, we can say India is much bigger in terms of population, however EU is little bigger in size. But in terms of diversity, India and EU is comparable. Both of them have age old heritage and cultural background.
But EU consists of independent states mainly on the basis of languages and cultures. There is least overlapping between them. Most of them are do not like each other and in past there were many conflicts between them. Even in last few decades Europe has given birth of many small countries (Split of Yugoslavia, Czechoslovakia).
Where as India is purely a secular democratic country. Hindi being the national language, we have 22 other official languages and many more sub languages. Irrespective if cultural and racial differences of different States, there is no urge to get separated. The underlying fundamental unity is flowing in Indian Culture.