Real estate investment trusts or Reits in India have faced a decline in overall portfolio vacancy levels by 4-6% due to continued work-from-home and the second wave leading to deferment of leasing decisions by occupiers.Vacancy levels in offices may see a further rise in the first half of 2021-22, by an incremental 2-3%, though the trend may reverse in the latter half assuming vaccinations pick up accompanied by a gradual return to offices and a possible pick-up in international travel, said a new report by ICICI Securities Ltd.In terms of performance, all the three office Reits – Embassy Office Parks, Mindspace Business Parks and Brookfield India – saw strong rental collections of over 99% in 2020-21 and were able to achieve double digit.