Coach Mark Lane has warned England that retaining the Women's World Cup this year will be harder than winning it.
England lifted the trophy with a thrilling four-wicket victory over New Zealand in Sydney four years ago.
Captain Charlotte Edwards will lead the team in India as they attempt to defend their title. Their first match is against Sri Lanka on 2 February.
"Defending a title is harder then winning it in the first place," Lane told the BBC's Test Match Special.
"Once you get to number one, you have to stay ahead of the pack and a lot of that comes down to hard work.
"We are there to be shot at but we are not worrying about what other people think. We are concentrating on what we do.
"We know what we are going to do and we will be focused on that."
Edwards is one of eight players in the 15-strong squad who were in the victorious 2009 squad.
England World Cup squad: Tammy Beaumont (wk), Arran Brindle, Katherine Brunt, Holly Colvin, Charlotte Edwards (capt), Georgia Elwiss, Lydia Greenway, Jenny Gunn, Danielle Hazell, Amy Jones (wk), Heather Knight, Laura Marsh, Anya Shrubsole, Sarah Taylor (wk), Danielle Wyatt.
Women's World Cup 2013: England's matches
28 Jan Warm-up v South Africa, Mumbai (Brabourne Stadium) (03:30 GMT)
29 Jan Warm-up v New Zealand, Mumbai (BKC) (03:30 GMT)
1 Feb Group A match v Sri Lanka, Mumbai (Brabourne Stadium) (03:30 GMT)
4 Feb Group A match v India, Mumbai (Brabourne Stadium) (03:30 GMT)
5 Feb Group A match v West Indies, Mumbai (BKC) (03:30 GMT)