Is it permissible for us to pray in impure clothes and with an insufficient ablution, or to delay the Dhuhr and Asr prayers until returning home and purifying ourselves, or is it obligatory to pray on time with tayammum?

Whoever goes to a place where water is unavailable should purify himself and take water with him, and be careful to avoid impurity. If impurity afflicts him and he is unable to remove it, he should pray in his garment and repeat the prayer when he is able to purify or change it. If he nullifies his ablution and does not find water, he should perform tayammum (dry ablution) and pray, and he does not need to repeat the prayer. It is not permissible for him to delay the prayer to combine them after his return. The default state of things is purity, and one does not deviate from it except with certainty or strong presumption.