The credit card limit is not only related to your monthly income, but also related to your other assets. Personal financial proof should be submitted when applying for a credit card. The more certificates submitted, the higher the limit. General financial certificates include real estate license, automobile driving license, deposit certificate and credit card.
If you have less information in this field and want to increase the quota, you can make more efforts in choosing the issuing bank. The five major state-owned banks suggest not to apply, and the review is very strict. You can choose which commercial banks to handle credit cards, or you can choose the bank where the salary card is located.