How are ECR passport checks enforced in India?

If an Indian passport applicant does not fulfil certain conditions, then the passport has “Emigration Check Required” printed in it.(Note: I can’t find a current image of such a print)

India has exit border checks and each passenger’s passport and boarding card is checked and stamped by the border agent. From the Bureau of Immigration website (emphasis mine):

Indian nationals travelling abroad require a valid Indian passport and
travel authority for the destination country.

The travel authority is normally in the form of Visa, which is
obtained prior to the journey, except in case of countries where “Visa
on Arrival” is available.

Indians traveling abroad may also note that some countries insist for
certain minimum period of passport validity for allowing entry & for
this confirmation should be obtained from the Embassy/travel agent.

Indians having the Emigration Check Required (ECR) category of
passports require POE clearance from Ministry of Overseas Indians
Affairs for certain destinations if traveling on Employment Visa.

The “certain destinations” are:

United Arab Emirates (UAE), The Kingdom of Saudi Arabia (KSA), Qatar,
Oman, Kuwait, Bahrain, Malaysia, Libya, Jordan, Yemen, Sudan,
Afghanistan, Indonesia, Syria, Lebanon, Thailand, Iraq (emigration
banned).

The ECR check thus is enforced by Bureau of Immigration. A passenger with a passport that has the ECR stamp, and travelling to the specified countries on an employment visa needs to have an “Emigration Clearance” from the Protector of Emigration(PoE). From the (somewhat flaky) website of PoE Chennai (empahsis mine)

‘Emigration clearance (EC) is a kind of legal authorization for
‘emigration’ obtained in the prescribed manner and form from the
Protector of Emigrants (POE). Emigration clearance is issued under
provisions of Sec 22(1) of the Emigration Act 1983. This
authorization is currently issued in the form of a ‘security sticker’
duly signed by the POE and gets pasted on the Passport of the emigrant
who requires Emigration clearance

The procedure to obtain such a clearance is given here. The applicant needs to submit a few documents (employment contracts and insurance) for getting a clearance.

Thus ECR check at border is done by checking the passenger’s passport/visa and if the passport has an ECR stamp, then the “Emigration Clearance” sticker for the destination country. In case the passenger does not have these, he/she will not be allowed to leave India. Immihelp provides more information about “special” one time clearances in exigent circumstances, but I cannot find an official link for the same.

Also note that for any other type of visa for travel to the ECR countries, the emigration clearance is not required provided the passenger can show return tickets. From the Ministry of external affairs website:

ECR passport holders going to any of the notified countries (ECR
countries) on any visa other than employment visa, are allowed to
travel on production of following documents at the Airport:

Valid Passport

Valid visit/residence/study visa etc.

Return Ticket

For your other question

And how does it work for Indians departing from bordering countries,
such as Nepal?

I am not sure. As ECR check is done by Indian border officers, presumably there is little they can do if the passenger departs from Nepal or other neighbouring countries.

If you did not attach 10th class certificate (Matric) while applying for passport, you used to get passport with words printed on second page :” Emigration Clearence Required blah blah blah….” Then you were supposed to go to passport office again (people also used touts with cost about 1000 Rs) to get this paragraph striked, and Passport Officer’s signature and stamp saying ECNR on same page.

If you attached educational certificate, then it used to get striked auto on issuance.

If you are going on a work visa to Gulf or few other countries, and has ECR status, border control will notice and will not let you go out of country without ECNR. Immigration officer will make you go back and get the ECNR from passport officer of your area/district. This essentially means you will miss the flight.

Regarding the try to circumvent it, by going to Nepal and flying from there, I believe this is possible, as many people go to Iraq/Syria etc for work (because agents promised them moon and back salaries because of war zone) via Dubai/Nepal. India does not allow people to go to Iraq/Syria for work, so people just say, have visa, for Dubai/Gulf.

Like any other country, you check-in at airline counter, get boarding passess, and need to go through immigration if international flight. There Immigration Officer will check boarding pass, will ask the reason of travel, and might want to see the documents you will use to enter your destination. If the destination is on list, and you are going for work, he will check the ECR/ECNR/POE, and you essentially will not be allowed to cross the border (need to go back to sort it).

Relevant Quote from Buraeu of Immigration, India

As per the Emigration Act, 1983, Emigration Check Required (ECR) categories of Indian passport holders, require to obtain “Emigration Clearance” from the office of Protector of Emigrants (POE), Ministry of Overseas Indian Affairs for going to following 18 countries.

United Arab Emirates (UAE), The Kingdom of Saudi Arabia (KSA), Qatar, Oman, Kuwait, Bahrain, Malaysia, Libya, Jordan, Yemen, Sudan, Afghanistan, Indonesia, Syria, Lebanon, Thailand, Iraq (emigration banned).

Some more info from ImmiHelp

this website does not allow me to select text on mobile?

Source: I co-ordinate between 70+ mixed nationalities employees and Official HR Department for these all visa/travel related processess in a Gulf Country.