Hi shriya,

Yes if your interested to join that college then  you have to pay challen to hold that college or Else you may loose seat because in second counselling if you get better then before college then you can  join (o r) if you fail to get good college in second counselling then you have option to join 1st counseling college if you paid challen for 1st counseling college 

 If you what to hold the seat then you have to pay challen or else it's not complesary to pay just you loose ur first counselling seat if you are not paid