1. Astana is visited by millions of tourists every year.
2. Saryarka velodrome is used mainly for track cycling events.
3. President’s Cup tennis tournament is held at the Dailey National Tennis Center every year.
4. 30,000 spectators are held in the Astana Arena stadium.
В Пассиве действие происходит над подлежащим (Астану посещают, велодром используют и тд)
В present simple passive am/is/are + V3(глагол в 3 форме: окончание -ed или индивидуальная форма неправильного глагола). Например, Astana IS visitED