Tharus are the mainland Terai people. Then all other Indian origin madhesi friends should leave terai at let the Tharus rule them. After the eradication of Malaria and clearfelling of Charkoshe Jhadi, Mostindians cme and settled in the terai area. That time Nepal's population growth was around 1.27 or so but due to that in migration from India it reached at that time upto 4.6 per annum.