Vaisheshikasutra 5.2.3

5.2.3

apāṃ saṃyogābhāve gurutvāt patanam |

apām—of waters; saṃyoga-abhāve—in the absence of conjunction; gurutvāt—from gravity; patanam—falling.

3. The falling of waters, in the absence of conjunction, is due to gravity.—201.

[Read sūtra 5.2.3 above]

The falling of waters, in the form of a shower, is caused by gravity, which is its non-combinative cause. It takes place in the absence of conjunction, i.e., conjunction with the cloud. Therefore, absence of conjunction is the efficient cause. This is the meaning.—3.