NEW DELHI: When Prime Minister Narendra Modi launched the Bhim app last week, the common platform for the Unified Payment Interface was touted as the next big thing that would help widen the adoption of cashless transactions in the country.Yet, the National Payments Corporation of India, the agency that handles all retail payment systems in the country, is “getting impatient” with companies such as Flipkart Paytm and Indian Railway Catering & Tourism Corporation for taking time to integrate with UPI, which forms the core of Bhim.That’s because customers who have downloaded the app aren’t finding enough avenues to use it because merchants – especially online ones that are expected to generate the bulk of such payments – have been slow to warm up to the new system.AP Hota, managing director, said NPCI is “not very happy” with the 70,000 UPI transactions a day, the figure before the Bhim app was launched on December 30. NPCI said that as on Wednesday, the number of transactions had increased to 1,90,000 per day.UPI is a system that brings multiple banks on to a single mobile application , merging several banking features, seamless fund routing and merchant payments, according to the NPCI website. The app was developed by NPCI and launched in August.“Whenever we speak to them, they say that they are talking to the banks. I fail to understand…” Hota told ET last week. He said that while companies have shown interest, they are still assessing and negotiating commercial terms with banks.To be sure, Hota said the Flipkart-owned payment app PhonePe is the largest user of UPI, although it is primarily used to top up the mobile wallet.“Their main promoter Flipkart is not using it significantly,” Hota said.The same is the case with Snapdeal-owned digital wallet Freecharge, which is the second-largest user of UPI and has opened it up only for top-ups. In the case of Paytm, money added to the account through UPI is minimal, he added.“Some travel and ticketing sites have joined, but none of the top 15 merchants of UPI are the top merchants of the country yet,” Hota said.The government has been encouraging a shift to cashless transactions after it demonetised Rs 500 and Rs 1,000 currency notes on November 9. The value of UPI transactions surged to Rs 700 crore in December from Rs 90 crore in November as volumes increased more than six-fold to 2 million last month, according to provisional data on the Reserve Bank of India website. Still, UPI commands only a minuscule share of non-cash transactions by both volume and value.NPCI expects dealings through UPI to get a major boost once it is integrated as a payment option for ecommerce customers, along with net banking, card payment and cash on delivery.Ecommerce platforms offer a large potential in scaling up such transactions. Flipkart did transactions worth Rs 1,400 crore on a single day during its flagship ‘Big Billion Day’ sale in October. IRCTC, the state-run railway ticketing agency, sells about 6 lakh train tickets a day through its website.About 400 merchants had signed up for UPI as of last week. Snapdeal and Amazon did not comment on the matter.Sameer Nigam, cofounder of Flipkart’s PhonePe, said the feature to pay through UPI on Flipkart is currently live for 5% of the customers and will likely be rolled out for the rest by next week. PhonePe’s Android app had already integrated UPI when it was introduced and the iOS version was launched two days ago, he said.Nigam added that the reason behind the phased approach is because the system needs to stabilise since there can be scaling-up issues at the end of both the banks and NPCI. “Its growth is so fast, especially after the PM launched the new app,” he added.A spokesperson for IRCTC said integration of UPI is currently “under process” and will happen “soon.”Paytm “made live” the UPI feature for wallet top-ups last week. “Linking of UPI with ecommerce and the purchase of flight and movie tickets will take place after its payments bank is launched. Customers will then be able to pay directly from their Paytm bank accounts,” said Deepak Abbot, senior vice president, product growth at Paytm.Abbot said one reason for the slow adoption of UPI could be the complex nature of using it.“One has to create a UPI ID, which is ‘some name@some bank’ and most people are getting confused about it. We have noticed that the biggest reason why transactions are failing is because people are writing the wrong ID. Even after Bhim, it is supposed to be ‘mobile number@upi.’ This needs to be simplified,” he added.