Union revenue secretary nudged the indirect tax officers to try and garner about Rs 1.5 trillion as monthly GST collection from October onwards by ensuring better compliance and plugging leakages.“For the last couple of months we have been trying very hard to reach that milestone of Rs 1.5 trillion, but we have been falling short sometimes by Rs 2,000 crore and sometimes by Rs 6,000 crore,” he said addressing tax officers at an event in Mumbai to inaugurate a housing project for GST personnel.