O limite não caiu, ao passo que o endividamento diminuiu.

In Portuguese, definite articles are used more often than in English. Here, o limite and o endividamento mean the limit and the indebtedness/debt level.

Even when English might drop the in some contexts, Portuguese often keeps it. So this sentence sounds natural with:

• o limite
• o endividamento

Both nouns are masculine singular, so the article is o.

Ao passo que is a connector meaning something like:

• whereas
• while
• whereas at the same time
• in contrast, while

It introduces a contrast between two facts:

• O limite não caiu
• ao passo que o endividamento diminuiu

So it is comparing two different trends: one thing did not go down, while the other did.

This expression is a bit more formal and more common in written or careful speech than very casual conversation.

Yes, usually it sounds somewhat formal or written.

In everyday Brazilian Portuguese, people might more often say:

• mas
• enquanto
• já
• só que in very informal speech

But ao passo que is perfectly correct and natural, especially in:

• news
• reports
• academic writing
• business or financial language

So this sentence has a slightly formal, analytical tone.

Both are in the pretérito perfeito of the indicative, which usually corresponds to the simple past in English.

• caiu = fell / went down
• diminuiu = decreased / went down

Their infinitives are:

• cair → caiu
• diminuir → diminuiu

So the sentence talks about completed past events or changes.

Both verbs can refer to reduction, but they are not exactly the same.

• cair literally means to fall
• diminuir means to decrease / reduce

In Portuguese, cair is often used metaphorically for things like:

• prices
• rates
• sales
• levels
• limits

So o limite caiu would sound natural as the limit fell/went down.

Diminuir is a more general verb for becoming smaller or lower. With endividamento, it works very naturally:

• o endividamento diminuiu = the debt level decreased

So the sentence uses two different but compatible verbs to describe two trends.

Yes. In Portuguese, cair is very commonly used with abstract or numerical things.

Examples:

• Os preços caíram. = Prices fell.
• A taxa caiu. = The rate fell.
• A demanda caiu. = Demand fell.
• O limite caiu. = The limit went down.

So this is not unusual at all. It works much like English fall in economic or statistical contexts.

Endividamento refers to the state or level of being in debt. Depending on context, it can mean:

• indebtedness
• debt level
• level of debt

It comes from endividar(-se), which relates to getting into debt.

So:

• o endividamento diminuiu = the indebtedness decreased
• more naturally in many contexts: the debt level decreased

It is a common noun in financial, business, and economic language.

The comma is used because ao passo que introduces a contrasting clause.

Structure:

• O limite não caiu,
• ao passo que o endividamento diminuiu.

This pause helps separate the two ideas clearly. In formal writing, this punctuation is very natural.

It is similar to how English often uses a comma before while or whereas when contrasting two clauses.

Yes, often you can, but the nuance may change slightly.

• ao passo que strongly emphasizes contrast
• enquanto can mean while, and depending on context it may suggest either time or contrast

For example:

• O limite não caiu, enquanto o endividamento diminuiu.

This is possible and natural, but ao passo que sounds a bit more explicitly contrastive and formal.

If you want a clear comparison in a more formal register, ao passo que is a strong choice.

Yes, you could say:

• O limite não caiu, mas o endividamento diminuiu.

That is grammatically correct and very natural. It sounds simpler and more conversational.

The difference is mainly style:

• mas = straightforward but
• ao passo que = more formal whereas / while by contrast

So both work, but ao passo que sounds more analytical.

In standard Portuguese, negation normally goes before the verb:

• não caiu
• não diminuiu
• não aconteceu

So O limite não caiu is the normal standard order.

In some varieties of spoken Brazilian Portuguese, you may hear não repeated or placed later for emphasis, but that is more colloquial and not what you would usually write in a sentence like this.

Because each verb agrees with a singular subject:

• O limite → singular → caiu
• o endividamento → singular → diminuiu

If the subjects were plural, the verbs would also be plural:

• Os limites não caíram...
• Os níveis de endividamento diminuíram...

So this is a straightforward case of subject-verb agreement.

Yes, but the original order is the most neutral and natural.

Original:

• O limite não caiu, ao passo que o endividamento diminuiu.

You could sometimes move things around for emphasis, but that would usually sound more marked or literary.

For learners, it is best to keep this basic pattern:

• subject + não + verb, ao passo que + subject + verb

That word order is clear, standard, and very natural.