BANGALORE, India—Call-center company 24/7 Customer Pvt. Ltd. is desperate to find new recruits who can answer questions by phone and email. It wants to hire 3,000 people this year. Yet in this country of 1.2 billion people, that is beginning to look like an impossible goal.

So few of the high school and college graduates who come through the door can communicate effectively in English, and so many lack a grasp of educational basics such as reading comprehension, that the company can hire just three out of every 100 applicants.

...