The slums of Mumbai are a long way from the Austrian Alps, but Rodgers and Hammerstein’s timeless score for “The Sound of Music” transcends generations and continents to inspire the children of the Bombay Chamber Orchestra. This rousing documentary focuses on charismatic eleven-year-old Ashish, who has to overcome his anxieties as he prepares to sing a solo during the orchestra’s performance at Mumbai’s prestigious National Centre for the Performing Arts. As the big day approaches and excitement mounts, The Sound of Mumbai illustrates how these astonishingly talented children can use art to rise above their impoverished circumstances.