Who can file Form ITR-1 (Sahaj)?
Resident individuals whose income sits inside the form's eligibility conditions, and not non-residents. That is the whole of it, and those conditions are the substance of the question rather than a footnote to it. The form exists to be the simplest Indian return, and it achieves that by excluding everything that complicates a return: foreign assets, capital gains, more than one house, and non-residence itself. If your position includes any of those, the answer is that this form is not yours, and the useful work is identifying which form is.
Can an NRI file Form ITR-1 (Sahaj)?
No. Residence is an eligibility condition of the form rather than a box on it, so a non-resident is outside the form however simple their Indian income happens to be. This catches people out because the income often does look simple, a bank account and perhaps one let property, and the form is the one they used before they left. Filing it as a non-resident does not produce a completed filing. It produces a defective return notice, and the year stands unfiled while that notice is dealt with.
I own two houses. Can I still use Sahaj?
No. More than one house puts a filer outside the form. That is one of the eligibility conditions, and the conditions are not matters the form accommodates with an extra schedule; they decide whether the form may be used at all. The practical consequence is worth stating plainly, because it is the part people underestimate: a return filed on a form the filer was not eligible for produces a defective return notice rather than a completed filing, so the year stays open until it is replaced. Settle the property position first, then choose the form.
Can I use Sahaj if I sold shares or property in the year?
No. Capital gains are outside the form, and this is the exclusion that catches the most people, because a disposal can be a single transaction in an otherwise plain year while the rest of the return looks exactly like a Sahaj return. The reason is structural as much as formal: a gain has to be computed from cost, consideration and holding period, and the simplest form does not carry the schedules that computation needs. So where there has been a disposal, that is the first thing to establish, before any form is opened.
Can I file Sahaj if I hold foreign assets?
No. Foreign assets are one of the exclusions, and again the reason is structural: disclosing assets held outside India needs schedules the simplest form does not have, so a filer holding them cannot report a complete position on it. This is the condition that most often bites people with a cross-border history, whether that is an account left behind after a posting, a holding in an employer's overseas plan, or a property abroad. It is worth testing before the form is chosen, because an asset does not have to produce income to put you outside the form.
What happens if I file ITR-1 when I was not eligible?
You get a defective return notice rather than a completed filing. That is the practical answer to the eligibility question, and the reason it deserves attention before filing rather than after. A defective return is not a filed return, so everything that depends on having filed is unsettled while the notice is answered, and the correction has to be made inside the period the notice allows. The remedy is to file again on the form that fits the position, which means the eligibility analysis happens anyway, only later and to somebody else's deadline.
How do I get a refund of TCS collected on a foreign remittance?
You claim it on your Indian return for that year. The collected amount is credited against your total tax, and if it exceeds the tax due the balance is refunded like any excess payment. Two practical conditions: the collector must have filed its statement so the credit appears in your annual tax statement, and your PAN must be correctly recorded on the remittance. A salaried remitter can also ask their employer to account for it against salary withholding. See LRS limits and TCS.
How does an NRI prove residence to get the treaty rate?
With a tax residency certificate issued by the country you are resident in, plus Form 10F giving the details the certificate does not carry, plus a PAN in the payer's records. The certificate has to cover the period of the payment, and the payer needs it before paying, not afterwards. Missing any of the three and the deductor is obliged to withhold at the domestic rate, which turns a rate reduction into a refund claim. See TRC against Form 10F.