"All over the world there are people who hate each other," Mehta, 78, who is holding the baton for a fifth time at the annual waltz fest beamed live to 50 million people worldwide, told Austrian daily Die Presse.
"This music can at least bring people together for two and a half hours," he said.
Indeed, the 90 or so countries able to watch Thursday's concert live include for the first time conflict-riven Ukraine, as well as other newcomers as far afield as the Bahamas, Armenia and Mehta's native India, organisers said.
The Vienna Philharmonic's annual "Neujahrskonzert" ringing in the new year from Golden Hall of the exalted Musikverein is devoted largely to the kings of 19th century waltz, the Strauss family.
Each year has some variety, however. Last year, alongside favourites like "The Blue Danube" and "The Radetzky March", with Daniel Barenboim conducting, the programme included works commemorating the centenary of the start of World War I.
This time the occasion is a happier one, with music marking the 650th birthday of Vienna University as well as the 200th of the Austrian capital's Technical University and the 150th of Vienna's grand Ringstrasse boulevard.
These include for example "Accelerationen" ("Accelerations") and the "Elektro-magnetische Polka" by Johann Strauss junior, as well as his "Studenten-Polka" ("Students' Polka").
Non-Strauss pieces include the "Champagne Galop" by 19th century Danish composer Hans Christian Lumbye — which starts with the pop of a champagne cork.
Certain works such as "Wein, Weib und Gesang" ("Wine, women and song") will be accompanied by ballet performances by Vienna State Ballet soloists choreographed by Italian Davide Bombana.
"Certain traditions give people a feeling of safety," said Andreas Grossbauer, the Vienna Philharmonic's new chairman.
"Bedtime stories, birthday cakes — and perhaps also the New Year's Concert."
The event started life on December 31, 1939, under the Nazis but in the subsequent years these dark beginnings were forgotten and it gradually became a much-loved, regular event in the classical music calendar.
In the 1980s after the 25-concert reign of Austrian Willi Boskovsky and six-times American successor Lorin Maazel — who died this year — it was decided to have a different conductor each year.
These have included such greats as Herbert von Karajan, Claudio Abbado — who also passed away in 2014 — and Mehta in 1990, 1995, 1998 and 2007.
The Mumbai-born conductor, who first came to Vienna to study in 1954 and whose posts have included music director of the New York Philharmonic, said though that he was "just as excited" as before his debut 24 years ago.
"I can think of no greater (honour)," he said. "When I walk from the Imperial (hotel) towards the Konzerthaus of the Musikverein, it's like I was in my living room. I feel so at home here."