NEW DELHI: The assessment conveyed by experts to the government was urgent: The number of Covid-19 patients would increase as people returning to India carrying the infection would come into contact with others and this required an immediate response.Senior officials dealing with public health were unanimous in their opinion that a lockdown was the need of the hour. People needed to be immobilised so that those who developed symptoms would not become spreaders on a scale that would send the number of Covid-19 patients — and mortalities — soaring.The three-week lockdown announced by Prime Minister Narendra Modi exceeded expectations within the government where experts felt that they may get less. A 21-day lockdown would allow the key teams monitoring the disease to push measures related to social distancing, symptom-based testing and expanded scrutiny of patients with serious respiratory illnesses to the fullest.While the largescale migration of people took officials by surprise, they still feel the lockdown will deliver benefits as appeals for work from home were being flagrantly violated. The benefits are seen in terms of stabilising numbers and ensuring that the disease does not spread exponentially in the community.