Here’s the data for number of seats for each election year.
1952 – 489 seats
1957 – 494 seats
1962 – 524 seats
1967 – 520 seats (interesting to note that it has decreased)
1971 – 518 seats
1977 – 542 seats
There has been no change after 1977.
542 seats for 130 crore people, means each MP represent aspirations of about 25 lakh people.
For serious work to happen on ground and to hear the voice of people, I think, this should not be more than 5 lakh. Let us hope Election Commission does some serious deliberation on this matter.