As TRAI reportedly wants to regulate caller ID apps and restrict 'spam' and 'frequently blocked' labels on 140-series (promotional) and 1600-series (service/transactional) numbers, Truecaller CEO Rishit Jhunjhunwala said this will fuel spam calls in India. Users block four lakh 140-series and 1.25 lakh 1600-series calls daily, he said. Over 51 million such calls go unanswered every day, he added.