.In Indian federal democracy

[1 Nation + N States, UTs, and further decentralization of power], the Population of the state holds a major political & economic significance. Population control in South India is far better than in North India and it was only possible because of the social development and economic growth of the South. As I said, Population holds a significant role and so changes in population geography create a bigger impact.

Article 81 of the constitution states: Lok Sabha Constituency[MPs] should be in proportion to population size. more population means more number of constituency and hence more number of MPs in parliament. but the number of MPs has been frozen since 1976. Based on the population census of 1971, In 1976 through the 42nd Constitutional amendment, the count of MPs was frozen till 2001( for 25years ), in 2001, by the 84th amendment, the count was frozen til 2026( again for 25 years ).

you see the population trajectory of the South and north,Between 1971 and 2011, the share of Northern States(BR, CG, GJ, JH, MP, RJ, UK and UP) Population rise from 44% to 48.2%, while the southern state(Andhra Pradesh, KA, KL, TN, Telangana) proportion declined from 24.9% to 21.1%

Population control happens not only due to the implementation of family planning programs but also because of the social change that is engineered by the leaders in the society.

If we apply Article 81 now, based on the 2011 population census, the North will gain 37 Extra Lok Sabha Constituencies while the South will lose 23 Lok Sabha Constituencies. which'll be a disincentive to the South on the other side it'll be an incentive to the North for not being serious about controlling to population.

and thus Frozen number of MPs(till 2026) is the only option to have a better political representation from the South and North parts of India.

Population & Finance Commission(FC):

FC is constituted by the Union Government once in five years to take care of the distribution of "financial resources including Revenue generated by Taxes" to various states[KA, TN, UP, BR, KERALA+24others + UTs]. while the commission decides the formula to distribute the revenues, the Population and per capita income of the states are the two major parts of the formula.

1st Finance Commission decided a State’s share based on its population size. in successive years population criteria were lowered while other variables were increased.

8th Finance Commission (1984-89), stipulated to use of only the 1971 population in the distribution instead of the 1981 population.

14th Finance Commission, the Union government stipulated that apart from taking the 1971 population, the Commission may also consider demographic changes since 1971, wherever the population is to be used. : by adding demographic changes, the North was able to get more financial help from the Center, while the South didn't get much. the reverse effect of controlling the population.

15th Finance Commission openly declared taking the 2011 population in the distribution formula. Therefore, the southern States have already started facing reduced financial transfers from the Union government as a reward for controlling population growth.

The 2nd Major Factor in the distribution of financial help, apart from the population is Per Capita Income[PCI].

If the PCI of Karnataka is 80k Per Person & PCI of MP is 60k then, MP is entitled to receive more financial support from the center than Karnata: Lower the PCI More the support from the Union government as per Finance Commission Recommendations.

Using The Current Population for Delimitation of Lok Sabha Constituencies as per Article 81: South will lose Political Representation due to reduced MPs.

AND

Using the Population as the major variable to distribute Financial Support to the state, too, will be a disincentive to the South despite controlling the Population.

okie, by thenks :)