وَيَنْبَغِي أَنْ يُؤَذِّنَ وَيُقِيمَ عَلَى طُهْرٍ
Translation: It is fitting to deliver both adhan and iqamah in a state of ritual purity.
Tuhr here refers to ritual purity, normally wudu. Giving both calls in a pure state is the recommended manner due to their relation to prayer.
The next clauses distinguish adhan without wudu from iqamah without wudu, showing that the cases are not treated identically.