S. R. Faruqi:

The consummateness and simplicity of the simile are in a class by themselves. In olden times, when an army was in motion, it used to live off the land. In such circumstances, for an army to pass through (even if it would be the army of one's own king) was synonymous with despoliation and devastation. The word ābādī is also fine, because after the passing of an army the residents of that place used to be either in a wretched condition, or scattered and dispersed.

There are two meanings of jānā jātā hai . One is 'it's clearly apparent'-- that is, having seen the condition of the heart, it is plainly evident that some army has passed through this way. The other meaning is 'it seems as if'-- that is, the destruction of the heart is of such a degree as it would have been at a time when some army had passed through it.

In all verses of this type [is t̤araḥ ke tamām ashʿār] we can assume 'the heart' to be a metaphor for 'the city of Delhi' [dillī shahr]. In the verse below from the fifth divan, Mir has made this idea explicit [{1775,1}]:

dīdah-e giryāñ hamārā nahr hai
dil ḳharābah jaise dillī shahr hai

[our weeping eyes are a water-channel
the heart is a ruin like the city of Delhi]

Mir has used this theme again and again; but the appropriateness (especially the second line) with which he has used it in the present verse, he was never again able to achieve. From the second divan [{786,2}]:

dil kī vaisī hai ḳharābī kaṡrat-e andoh se
jaise rah paṛtā hai dushman kā kahīñ lashkar bahut

[the heart is in the kind of ruinedness, from the extensiveness of sorrow,
as if when an enemy's army settles for a long time]

From the second divan [{993,7}]:

ṣāf sārā shahr us anboh-e ḳhat̤ meñ luṭ gayā
kuchh nahīñ rahtā hai vāñ jis rāh ho lashkar chale

[clearly/cleanly, the whole city, in that rush of lines/'down on the cheek', was looted
nothing remains there, on the road by which the army set out]

Also from the second divan [{1021,2}]:

ḳharābī dil kī kyā anboh-e dard-o-ġham se pūchho ho
vuhī ḥālat hai jaise shahr lashkar lūṭ jātā hai

[the devastation of the heart, from the rush of pain and grief-- how can you ask?
it's exactly the same state as that of a city-- the army loots it]

Better than all these, and in a more eloquent [balīġh] style, without mentioning the army, he has composed in the first divan itself:

{52,4}.

An extremely fine [Persian] verse of Kalim Hamadani's is:

'Oh Kalim, against whose unjust hand would I lament?
Through my field an army has passed'.

It's probable that Mir might have obtained the basic theme from this verse. The power of Kalim Hamadani's verse is in the fact that those who oppress the speaker are countless. It's a whole army who have passed through, trampling down his fields. So about whose oppression should he complain? There's no one person who's the oppressor. There's also the point in it that there was one single person who was the oppressor, namely the chieftain of the army or the king of the army, but no complaint can be made against him, or the speaker has no power to make a complaint.

In Mir's verse the dramaticness is greater, and with the insha'iyah style of the first line, the second line's metaphorical expression has given a double pleasure. The zila of jān'nā [to know] and jānā [to go, infinitive of jātā] is also fine in its place.

FWP:

SETS == INEXPRESSIBILITY
MOTIFS
NAMES == DELHI
TERMS == DRAMATICNESS; SIMILE; THEME; ZILA

As SRF observes, the army could be a fine metaphor for general devastation ('Your room looks as if a herd of pigs has been living in it!'). Or it could be a powerful metaphor for the beloved's beauty-- for as the Song of Solomon has it, the beloved's beauty is 'terrible as an army with banners'.

But then SRF goes on to say that 'in all verses of this type' we can also take the heart as a metaphor for the city of Delhi [dillī shahr]. Now it's true that that reading makes for a wonderful double meaning, and is perfectly legitimate in {1775,1}, where that phrase appears. (Although dihlī is a more common spelling in Urdu, dillī also appears.) But I don't see any grounds for reading into the verse a particular reference to Delhi wherever the heart appears as a city trampled by armies.

After all, there are plenty of both real and imagined cities trampled by armies, and in the ghazal world a naturalistic reading is almost always secondary to a theme-based one, as nobody knows better than SRF himself. Moreover, if Mir indeed derived this theme from Kalim Hamadani's verse, as SRF also speculates, then plainly no identification with Delhi is necessary, since Kalim doesn't even speak of a city at all, but only laments the trampling of the field of his heart.

That second line is truly terrific, isn't it? The elegant wordplay and meaning-play of jānā jātā hai , with almost a marching rhythm, followed by the all-too-evocative simplicity of the army not just marching through but 'emerging'. Emerging from what inner depths of the heart? Emerging after what deadly feats of despoliation? Emerging with what kinds of precious valuables? It's beyond description-- don't even ask! The city of the heart is now something like a bare, dusty, much-trampled 'road'. Not only is the presence of the army devastating, but so too is the process of its departure; and even the aftermath of its departure is a scene of utter ruin.

Just for comparison, here's a verse with what seems to be a real, explicit, non-metaphorical Delhi reference [{87,4}]:

dillī meñ āj bhīkh bhī miltī nahīñ uñheñ
thā kal talak dimāġh jiñheñ tāj-o-taḳht kā

[in Delhi, today, they don't receive even alms,
they who up till yesterday had a pride in crown and throne]

This is the most descriptive-looking verse about Delhi that I've noticed in the whole kulliyat. And even in this case, it has a notably fatalistic, Sufistic, allegorical tone.