The Blackcaps have dropped to fourth in the one-day international rankings, after suffering a series sweep defeat to India and a 90-run loss in the third match at Indore.
Indian opening pair Rohit Sharma and Shubman Gill put on a 212-run first stand, with both reaching centuries, to set New Zealand 386 to win.
Devon Conway was the only Blackcaps batter to offer any resistance, with a quickfire 138 teasing an unlikely run chase, but found little support from his partners. No.3 batter Henry Nicholl's 42 was the next-highest score, as New Zealand fell to another heavy white-ball defeat.
Stand-in captain Tom Latham won the toss and sent the hosts into bat, which quickly proved a disastrous decision, with Sharma and Gill putting on a double-ton partnership.
Incoming bowler Jacob Duffy brought up an unwanted century with the ball, conceding 100 runs off his 10 overs for three wickets.
His bowling partners didn't fair much better, with Blair Tickner conceding 76 for his three wickets and Michael Bracewell going for 8.5 runs an over.
Sharma and Gill's dismissals in back-to-back overs offered a glimmer of hope for the Blackcaps, but fiery cameos from Virat Kohli (36), Hardik Pandya (54) and Shardul Thakur (25) saw India post 385/9 off their 50 overs.
The Blackcaps chase started disastrously, after opener Finn Allen was bowled by Pandya for a two-ball duck in the first over. Unlike his opening partner, Conway looked at ease at the crease and, together with Nicholls, put on a team-high 106-run partnership.
Conway's innings included eight sixes and back-to-back strikes into the crowd to bring up another century in black.
Nicholls' departure brought the underfire Daryl Mitchell to the crease and for 10 overs, he looked like he would join in on the high-scoring game, but after he was caught behind for just 24 runs, a middle-order collapse ensued.
Latham was dismissed for a golden duck the very next ball, with Glenn Phillips (5) and Conway following shortly after.
Michael Bracewell and Mitch Santner put on a 39-run partnership, but there were to be no heroics again from the forme,r after he was stumped for 26 off of Kuldeep Yadav.
The Blackcaps tail failed to wag, with Lockie Ferguson (7) and Jacob Duffy (0) dismissed inside two overs, before the final wicket of Santner fell, looking to clear Yuzvendra Chahal over the fence, but picking out Kohli in the deep to hand an emphatic series win to India and the No.1 world ranking.
India 385/9 (Gill 112, Sharma 101, Pandya 54; Tickner 3/76, Duffy 3/100) New Zealand 295 (Conway 138, Nicholls 42, Santner 34; Thakur 3/45, Chahal 2/43)
India win by 90 runs
