Skandapurana 5.167.5

5.167.5

tataścaiva jalāhārastāvanmātraṃ vyavasthitaḥ ..
kālaṃ sa vāyubhakṣaśca tataścaivāyutaṃ samāḥ.. sūta uvāca..
atha dṛṣṭvā tapaḥśaktiṃ tasya tāṃ tridaśādhipaḥ.
pātāyaṣyati māṃ nūnameṣa sthānānnṛpottamaḥ... .. 5 ..

And then he remained for just as long subsisting on water alone;
and then for ten thousand years consuming only air.
Sūta said:
Then, seeing that power of his austerity, Indra thought:
“Surely this best of kings will cast me down from my station!”