Maharashtra Police has registered15 cases against at least 156 foreign nationals who had attended the Tablighi Jamaat gathering in Delhi for violation of Foreigners Act during lockdown, an official said on Saturday.The cases were registered in Mumbai, Navi Mumbai, Thane, Amaravati, Nanded, Nagpur, Pune, Ahmednagar, Chandrapur and Gadchiroli, the police official said.All these persons had arrived in India on tourist visa, he said.They hail from countries such as Kazakhstan, South Africa, Bangladesh, Russia, Tanzania, Kyrgyzstan, Iran, Togo, Malaysia, Indonesia, Benin and the Philippines.All of them have been placed in institutional quarantine.The Delhi gathering of Talblighi Jamaat in March turned out to be a major coronavirus hotspot.