With people largely shunning postcards as a means of communication with the advent of modern technology, like emails and social media, procuring so many postcards had become a headache, party sources said.
As a way out, the BJP is toying with the idea of sending a mix of emails and postcards to the Prime Minister.
"If we don't get adequate number of postcards, we can always send emails. I think it will be a mix of postcards and emails. From areas with dearth of postcards, emails will be sent," state BJP General Secretary Sayantan Basu told .
The programme will start in a few days.
"One crore refugees will congratulate the Prime Minister for passing this law. They will thank him for his resolve to give them citizenship, and also to the BJP for fulfilling its promise," Basu said.
The party was with the refugees and they would acknowledge this through the letter, he said.
The Citizenship Amendment Act (CAA) seeks to provide Indian nationality to Hindus, Christ, Sikhs, Parsis, Jains and Buddhists fleeing persecution in Pakistan, Afghanistan and Bangladesh before December 31, 2014.
They will not be treated as illegal immigrants any more and will be given citizenship.
The BJP, which is wooing Hindu refugees from Bangladesh as part of efforts to come to power in Bengal by defeating the ruling Trinamool Congress (TMC) in the 2021 Assembly polls, is hoping to encash the CAA to spread influence among this section.
An unspecified number of people have entered Bengal from Bangladesh, or earlier when it was East Pakistan, since the 1940s. The state has twice seen major influx during the Partition in 1947 and the 1971 Bangladesh liberation war.
According to Mohit Roy, BJP refugee cell in-charge, there are no official records of those who came after 1972.
The CAA has led to intense protests in most parts of the country and over 20 people have died. Bengal too has been on the boil, with the CAA becoming a major flashpoint in the ongoing battle between the TMC and the BJP for the control of political turf.
Trains, buses and railway stations have been torched and damaged. Roads and train tracks were blocked by protesters soon after Parliament passed the legislation.
Over the past two weeks, the TMC has been holding rallies and processions all over the state against the CAA. The Congress and the Left parties too have hit the streets.
The BJP has also launched a statewide campaign supporting the legislation.
( With inputs from IANS )