While submitting the application for DSSSB, you have commited mistake by wrongly filling up of your passing from board of Delhi instead of from the board of Uttarpradesh. The other fillings are correct. You may check the website whether there is any provision for making correction/ corrections. If there is scope for correction, do the same at the earliest.
In case, there is not such a provision, write an application to the concerned official indicating the mistake and accordingly reflect the name of the correct board from where you have passed. This application has to be sent through the registered post with an acknowledgement receipt to be attached with the envelope. This will be a proof of your correspondance with the DSSSB officials.
In order to sort out this issue, you can straightway approach the office and for the same, the address is given below-
The Controller of Examinations,
Delhi Subordinate Service Selection Board,
FC - 18, Institutional Area,
Karkadooma, Delhi - 110092.