The ICC was forced to shift the tournament to 2022 due to affect on fixture-list amid COVID-19 pandemic.
Even though the host nation has done extremely well in tackling the deadly outbreak, the number of fixtures, including the global qualifier in July, being suspended meant that the governing body was left with no choice but to weigh in the diminished game time for all sides while making its decision.
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"It came down to the ability of the teams to qualify," Nelson told 'NZME', a local media group, with three qualifying spots yet undecided. India, England, Australia, South Africa and the hosts had already confirmed their presence in the tournament through the ODI Women's Championship.
"We've done a lot of contingency planning around this event, to give it the best possible chance of proceeding successfully - ultimately the decision to delay it comes down to cricket," Nelson said.
"No qualifying tournaments have been able to be held yet, so in order to qualify and then compete in the event in 2021 – it was too risky."
"We've got teams that can't train, they can't assemble – in the case of a country like the West Indies they can't leave their islands to bring the team together - and that's just not a feasible way to ask a team to prepare for their pinnacle event," she added.
While prominent women's cricket personalities such as England captain Heather Knight and Australia wicketkeeper Alyssa Healy have made their disappointment clear with regards to the ICC's forced call, Nelson stressed that the deferment will only help these players prepare better for the quadrennial event.
"Having the tournament in 2022 gives the best possible chance for teams around the world to train, prepare, and come and compete in their pinnacle event," she said.
"We have absolutely no doubt we'll be able to pick up those plans and deliver an amazing event a year later."
(Inputs from PTI)