Hi Sharmila,
Thanks for reaching out. With regards to your concern about to Change status of placement to paused in each adgroup via AdWords API, You can use AdGroupCriterionservice with AdGroupCriterion.criterion field and set the status of userStatus to PAUSED. You can follow the code example here but add biddableAdGroupCriterion.setUserStatus("PAUSED") and change the keywordID to their placementID.
Let me know if you have any questions.
Thanks,
Nirmita Patel Google Ads Team