4.6 million peopleThe death numbers (4.2 million & 3.8 million) I used here, are the latest number.
The video used old numbers.
The World Health Organization estimates that 4.6 million people die each year from causes directly attributable to air pollution. Many of these moralities are attributable to indoor air pollution. Worldwide more deaths per year are linked to air pollution than to automobile accidents.
Air pollution - ScienceDaily
This is the first thing on google. So, there again, the numbers for outdoor air pollution are less, and most of them is common issues that may be exasperated due to air pollution, that is a bit of a stretch to associate most with air pollution.