The decision to skip a Hindi dub was primarily artistic and commercial:

Digital downloads and rentals are available through the Apple TV Store and Amazon Video .

Be cautious of websites or "audio track download" links claiming to offer a Hindi version of Dunkirk . These are typically:

At the time of its release, Warner Bros. India executive Denzil Dias noted that the film was the biggest opening for an English-only film in India, indicating that its core audience did not require a Hindi version for it to be successful. Where to Watch Dunkirk in India

Many sites using "Dunkirk movie Hindi audio track download" as a keyword may lead to malicious software or phishing links.

Does Christopher Nolan's Dunkirk ignore the role of the Indian army?