WASHINGTON  - US immigration authorities said they have begun taking applications for deferred deportations from young undocumented immigrants, an initiative that could benefit up to 1.7m people. A directive issued two months ago by Barack Obama allows undocumented immigrants to stay in the US if they were under the age of 16 when they arrived in the country. To be eligible, applicants also must be under 31 today, in school or have served in the US army, and have no criminal record. “Childhood arrivals who meet the guidelines and whose cases are deferred will now be able to live without fear of removal,” said Alejandro Mayorkas, head of US Citizenship and Immigration Services.