7月22日电，蒙牛乳业在港交所公告，计划发行可持续发展债券，债券发行所得款项将用于若干现有债务的再融资。

Group 1 - The core point of the article is that Mengniu Dairy plans to issue sustainable development bonds to refinance existing debts [1] Group 2 - The proceeds from the bond issuance will be used for refinancing several existing debts [1]