It looks pretty good to me. However, I think like dmc said it could be the weight of the toppings. Alternatively, it could be your hydration level or the type of flour. I know for myself, I get my best hole structure around 73-75% hydration. Anything more and I have found some structural problems with my doughs. Regarding the flour, I know you said things are limited in your area, you may want to talk to the local bakery to see if could purchase some of their flour.