Amid a state-wide Covid lockdown, thousands of farmers today set off from Karnal, Haryana, for Delhi, where they plan to observe May 26 as 'Black Day', marking six months of their protest against three central farm laws; The centre is likely to favour a short format test for the Class 12 board exams, and the state boards will be allowed to take their own decision, sources said; A study by Public Health England has found that two doses of the AstraZeneca vaccine were 60% effective against symptomatic disease from the variant first detected in India. The study also found that the Pfizer-BioNTech vaccine was 88% effective against symptomatic disease from the B.1.617.2 variant, two weeks after the second dose, and 93% effective against B.1.1.7 or the UK variant; and other top news of the day.