New Delhi: Absence of medical resources forced COVID-19 patients to fend for themselves and look for oxygen concentrator as an alternative to liquid medical oxygen (LMO) and even procure the device from overseas amid short supply, the Delhi High Court has said.The court made the observation while declaring as "unconstitutional" the Centre's decision to impose Integrated Goods and Services Tax (IGST) on oxygen concentrators which are imported by individuals or received as gifts for personal use.The verdict came on a plea by 85-year-old Gurcharan Singh, who was suffering from COVID-19, challenging the imposition of IGST on the import of oxygen concentrators as gift for personal use.