India has questioned the deportation of some students from India when they came to the U.S. with valid student visas to study at two Silicon Valley institutions which have denied being "blacklisted.There is definitely a glitch within the U.S. system. The U.S. consulate in Hyderabad issued F-1 student visas and they carried the requisite I-20 forms issued by the educational institutions certifying their admission.The Indian Embassy in US has taken up the matter with the State Department, the National Security Council and the Department of Homeland Security. Their response is still awaited.Sources also said that a couple of Indian consular officers who had gone to the San Francisco airport were not allowed to meet the Indian students who had been denied entry to the U.S. and put back on flights to India.On reports that some students had been denied entry because they had failed to satisfactorily answer immigration officers` questions at the port of entry, sources said there could be one or two such cases, but wholesale deportation of students pointed to a problem in the U.S. system itself.The sources also pointed out that the 14 Indian students from India who were deported last week and 19 others not allowed to board their Air India flights to San Francisco had all sought admission to California’s Silicon Valley University in San Jose and Northwestern Polytechnic in Fremont.