He breathed his last at the Intensive Care Unit (ICU) of the CMH around 11:15am, BNP organising secretary Syed Emran Saleh Prince told UNB.
Ruhul Alam was admitted to the CMH on March 10 with Covid-19 symptoms like fever and cough, and later tested positive for the virus.
The military-officer-turned BNP leader was shifted to the ICU of the hospital as his condition turned critical on March 13 last.
He is survived by wife, one son, one daughter and a host of relatives and well-wishers to mourn his death.
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He was buried at Banani Military Graveyard after Asr prayers.
Before the burial, his namaz-e-janaza was held at the graveyard in a limited way maintaining social distancing rules.
A BNP delegation, led by party vice chairman Shahjahan Omar, participated in the janaza.
On behalf of BNP, they also paid tributes to Ruhul Alam by placing a wreath at his coffin.
Born in Pekua of Cox’s Bazar on August 24, 1947, Ruhul Alam joined the Bangladesh Army in 1972 and went on retirement in 1998.
Ruhul Alam was made one of the advisers to the caretaker government formed by then President Iajuddin Ahmed in 2006.
He was made BNP Chairperson Khaleda Zia’s adviser in 2009 and the party vice chairman in 2016.
BNP acting chairman Tarique Rahman and secretary general Mirza Fakhrul Islam Alamgir expressed deep shock at the death of Ruhul Alam Chowdhury.
In separate condolence messages, they prayed for the salvation of the departed soul and conveyed their profound sympathy to the bereaved family members.