Whilst it is true that electricity was unavailable to most Indian villages during Mohandas K. Gandhi's lifetime, it can be expected that poles supporting, what seem to be power lines along the railroad right-of-way during Gandhi's tour of India, are instead supporting telegraph lines, some of which were in place as early as the 1850s.
When the Pakistani flag is being raised for the first time, the anthem that is playing is the modern national anthem of Pakistan ("Qaumi Tarana"). The original national anthem of Pakistan was a different song (written by a Hindu), which was written days prior to the ceremony and only lasted 18 months as Pakistan's anthem.
(at around 2h 20 mins) Footage of a speeding steam train is shown during Gandhi's visit to Britain in 1931. There were then only four railway companies in the UK, LMS, LNER, SR and GWR, all of whom proudly displayed their initials on their engine tenders. In the footage, however, there is only the smudge like the logo of British Rail, not formed until 1948.
When Lord Mountbatten arrives as the final Viceroy, as the National Anthem starts he salutes "Army" style, i.e. "up the long way". He was a Navy officer, and wearing the uniform of the Royal Navy, so his hand would have travelled "the short way".
When Gandhi tells the man how to escape from hell, the man prostrates himself at Gandhi's feet. Before, the man had tossed a piece of food on Gandhi's stomach. After falling at Gandhi's feet, the piece of food is gone.
In the opening scene in South Africa, Gandhi is riding first class on a steam locomotive. The first class car is shown as the forward car, closest to the engine. In passenger steam engines, first class would be the rearmost car, farthest away from the engine's heat and exhaust. Second or third class would be nearest the engine.
In the movie, The South African police were shown both arresting and beating Gandhi for burning passes during his protest of the Pass Law. Although Mohandas K. Gandhi and his fellow protesters were arrested for burning the passes, in reality neither Gandhi or any of the protesters were ever beaten by the police during the protest.
When Field Marshal Jan Christiaan Smuts signs in new legislation burdened by pressure due to protests resulting in the lawless burning of passes (i.e. registration certificates), the name under his signature reads "JAN CHRISTIAN SMUTS". The proper Afrkaans spelling would be "JAN CHRISTIAAN SMUTS" especially on official government documents.