I saw the TRPS and they decrease by .1 which is normal. Lets not panic.
First: There is IPL season going on. And this decrease has been due to the IPL. The range of 1.7-1.8 during IPL is not bad. Its actually good because 9 pm is the most competitive slot. The rival shows have history of doing well. The show will gradually pick post the IPL.
Second, all other SP shows are in the same. Many shows are getting lower TRPS than NK. Even the shows which are ahead of NK are in 1.9 to 2.1 range. Only YRKKH has 2.5 TRPS.
Third, the lead story has not even begun. Believe me, TRPS would increase once the lead story will start.
The new birth of Naamkaran has been successful because the show has got good TRPS post leap. Its due to IPL that this decrease has occur. So we need to support the show and hope that it would go up once IPL ends.